This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 097124507 filed in Taiwan, Republic of China on Jun. 30, 2008, the entire contents of which are hereby incorporated by reference.
1. Field of Invention
The invention relates to a fluorescent lamp and a manufacturing method thereof, and in particular, to a cold cathode fluorescent lamp (CCFL) and a manufacturing method thereof.
2. Related Art
The cold cathode fluorescent lamp (CCFL) is a mercury discharge lamp, and electrons inside the lamp impact upon mercury vapor atoms to make the atoms enter excited states after the high-frequency and high-voltage AC power is applied. The excited mercury atoms return to ground states by emitting ultra-violet rays, and the emitted ultra-violet rays again excite the fluorescent body of the CCFL to generate the visible light.
In the early ages, the CCFL containing the mercury is manufactured by directly adding the liquid mercury to the lamp. However, the content of the mercury cannot be finely controlled in this method, and the liquid mercury has the high vapor pressure, which may contaminate the working instrument and environment so as to generate significantly negative influences on the human body. At present, the CCFL containing the mercury is manufactured by providing a lamp tube having a light emitting chamber and a mercury accommodating chamber, disposing a dollop of mercury into the mercury accommodating chamber, heating the mercury accommodating chamber to release the mercury to the light emitting chamber, and then sealing the light emitting chamber and removing the mercury accommodating chamber.
In the conventional manufacturing method, however, the mercury releasing step needs very high heating temperature, and the released amount of the mercury can only reach the maximum of 80%. Thus, the other mercury cannot be reused and has to be thrown away. Thus, the cost is increased, and the product and environment contamination is caused.
In view of the foregoing, the invention is to provide a cold cathode fluorescent lamp (CCFL) and a manufacturing method thereof, wherein an amalgam with a low melting point can be used during the manufacturing processes so that the released amount of mercury can be increased, and the cost and the contamination of product and environment can be decreased.
To achieve the above, a cold cathode fluorescent lamp (CCFL) of the invention includes a light transmitting shell and an electrode disposed at one end of the light transmitting shell. The method for manufacturing the CCFL includes an exhausting step of exhausting a gas existing inside the light transmitting shell via a vent of the light transmitting shell, a charging step of charging at least one inert gas into the light transmitting shell, and an amalgam disposing step of initially disposing an amalgam inside a gas adjusting instrument, and removing the amalgam into a temporal region of the light transmitting shell after the exhausting step.
The amalgam is disposed inside an isolated space of the gas adjusting instrument and is isolated by a stopper. The stopper is moved away after the exhausting step to make the amalgam fall into the temporal region of the light transmitting shell.
A melting point of the amalgam is lower than an operation temperature of the exhausting step. The exhausting step is preformed by using a heating instrument to heat the light transmitting shell to activate the gas absorbed onto an inner wall of the light transmitting shell, so that the activated gas is exhausted. The gas adjusting instrument and the heating instrument are integrated as a single instrument. The inert gas is argon or neon.
The method of the invention further includes, after the charging step, a sealing step of sealing the vent of the light transmitting shell. A high-temperature torch is provided to seal the vent in the sealing step.
The method of the invention further includes, after the sealing step, a mercury releasing step of heating the light transmitting shell to make the amalgam release a mercury vapor. The temperature of the mercury releasing step is lower than 500° C. The mercury releasing step is performed by using the heating instrument to heat the light transmitting shell.
The method of the invention further includes, before the mercury releasing step, an impurity gas absorbing step of sputtering a material of the electrode onto the inner wall of the light transmitting shell by using a high-voltage AC power to drive the electrode. A metal layer or metal film is formed on the inner wall adjacent to the electrode during the impurity gas absorbing step for absorbing an impurity gas. The material of the metal layer or the metal film includes nickel (Ni), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe) or an alloy thereof.
The method of the invention further includes, after the mercury releasing step, a removing step of removing the temporal region by using the high-temperature torch, and sealing the light transmitting shell.
Preferably, the amalgam includes bismuth (Bi), tin (Sn), zinc (Zn), indium (In), lead (Pb) or a combination thereof. For example, the amalgam is a Bi—Sn—Hg alloy, a Zn—Hg alloy, a Bi—In—Hg alloy or a Bi—Pb—Sn—Hg alloy, or an amalgam with a low melting point. The weight percentage of Bi in the amalgam ranges from 4.0 to 60 wt %, the weight percentage of Sn ranges from 38 to 78 wt %, and the weight percentage of Hg ranges from 3 to 20 wt %.
In addition, the invention also discloses a cold cathode fluorescent lamp (CCFL) including a light transmitting shell, an electrode and a metal layer. The electrode is disposed at one end of the light transmitting shell. The metal layer is disposed on an inner wall of the light transmitting shell adjacent to the electrode for absorbing an impurity gas inside the light transmitting shell. The light transmitting shell is preferably a glass tube.
As mentioned hereinabove, the melting point of the amalgam used in the method for manufacturing the CCFL of the invention is not restricted by the operation temperature in the exhausting step. Thus, the amalgam with low melting point can be used, the released amount of the mercury can be increased, and the product and environment contamination can be avoided. In addition, the amalgam of the invention can be disposed inside the gas adjusting instrument, and then transferred from the gas adjusting instrument to the light transmitting shell directly after the exhausting step so as to simplify the manufacturing process. In addition, the invention further includes an impurity gas absorbing step of sputtering a material of the electrode onto an inner wall of the light transmitting shell to form a metal layer (or film), which can absorb the unnecessary impurity gas accommodated within the light transmitting shell, so that the light emitting efficiency can be enhanced.
The present invention will become more fully understood from the subsequent detailed description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
The method for manufacturing a cold cathode fluorescent lamp (CCFL) according to a preferred embodiment of the invention will be described with reference to
As shown in
The method for manufacturing the CCFL according to this embodiment includes an exhausting step of heating the light transmitting shell 21 and exhausting the gas via a vent 211 of the light transmitting shell 21. In the exhausting step, a gas adjusting instrument E2 is provided to exhaust the gas of the light transmitting shell 21, so that the impurity gas can be exhausted via the vent 211. Meanwhile, a heating instrument H2, such as an electric furnace, is provided to heat the light transmitting shell 21, so that the activated gas absorbed to the inner wall of the light transmitting shell 21 is exhausted. In addition, the gas adjusting instrument E2 and the heating instrument H2 can be integrated as a single instrument.
In this embodiment, the amalgam M2 can be disposed inside the gas adjusting instrument E2 in advance. For example, the amalgam M2 is disposed inside one isolated space E21 of the gas adjusting instrument E2 and is isolated by a stopper E22.
As shown in
The amalgam M2 of this embodiment includes bismuth (Bi), tin (Sn), zinc (Zn), indium (In), lead (Pb) or a combination thereof, such as a Bi—Sn—Hg alloy, a Zn—Hg alloy, a Bi—In—Hg alloy or a Bi—Pb—Sn—Hg alloy. Of course, any other amalgam with low melting point can also be applied to this embodiment. Taking the amalgam of Bi—Sn—Hg as an example, the weight percentage of Bi substantially ranges from 4.0 to 60 wt %, the weight percentage of Sn substantially ranges from 38 to 78 wt %, the weight percentage of Hg substantially ranges from 3 to 20 wt %, and the mercury releasing temperature is lower than 500° C. The amalgam of this embodiment has lower melting point. That is, the melting point of amalgam can be lower than the operation temperature of the exhausting step.
The method of this embodiment further includes a charging step by charging at least one inert gas into the light transmitting shell 21. In this embodiment, the gas adjusting instrument E2, which also has the charging function, is used to charge the inert gas (e.g., argon and neon) into the light transmitting shell 21 in the charging step. Of course, the charging step can also be performed by using any other charging instrument. The inert gas can form the plasma under the driving of the high-frequency high-voltage AC power.
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In summary, the amalgam used in the method for manufacturing the CCFL of the invention has the melting point lower than the heating temperature of the exhausting step. In addition, the released amount of the mercury can be increased to avoid the product and environment contamination. In addition, the amalgam of the invention can be disposed inside the gas adjusting instrument, and then transferred from the gas adjusting instrument to the light transmitting shell directly after the exhausting step so as to simplify the manufacturing process. In addition, the invention further includes an impurity gas absorbing step of sputtering a material of the electrode onto an inner wall of the light transmitting shell to form a metal layer (or film), which can absorb the unnecessary impurity gas accommodated within the light transmitting shell. Thus, the light emitting efficiency can be enhanced.
Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the present invention.
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