CN101994922A - Cold cathode fluorescent lamp for lighting - Google Patents

Abstract

A cold cathode fluorescent lamp for lighting includes a cold cathode fluorescent lamp tube and a driving unit. The inner tube diameter of the cold cathode fluorescent lamp tube is between 2.5 mm and 30 mm, and each of the two ends of the cold cathode fluorescent lamp tube has an electrode, and the ratio of the electrode emission current to the electrode electron emission area of the cold cathode fluorescent lamp tube is between 1.0 mA/ ^mm2 and 10 mA/ ^mm2 . The driving unit is electrically connected to the electrode of the cold cathode fluorescent lamp tube. Based on the above, the present invention provides a large-diameter cold cathode fluorescent lamp tube, whose inner tube diameter is between 2.5 mm and 30 mm, so that the electrode area can be greatly increased to allow a higher tube current.

Description

Cold Cathode Fluorescent Lamps for Lighting

technical field

The present invention relates to a cold cathode fluorescent lamp, in particular to a cold cathode fluorescent lamp for lighting.

Background technique

A cold cathode fluorescent lamp (Cold Cathode Fluorescent Lamp, CCFL) is a mercury discharge lamp. After passing through high-frequency and high-voltage alternating current, the electrons inside the lamp tube hit the mercury vapor atoms to make them reach an excited state (Excited State), and the excited mercury The atoms will return to the ground state (Ground State) by emitting ultraviolet light, and the emitted ultraviolet light will further excite the phosphor in the cold cathode fluorescent lamp to produce visible light.

At present, the inner diameter of the common cold cathode fluorescent lamps is mostly distributed between 1.4 and 2.4mm, and these CCFLs with small diameters have smaller electron emission areas of the electrodes, so that if the lamps are operated at a higher tube current In the state, the tube current of the lamp tube will be oversaturated because the ratio of the electrode emission current to the electrode electron emission area is too high, that is, the tube current exceeds the capacity that the electrode electron emission area can bear. In this case, although the power consumption of the CCFL becomes high, the excessive power consumption is actually converted into heat instead of light. In order to obtain higher operating power while maintaining good efficiency, it is necessary to use a cold cathode fluorescent lamp with a larger inner diameter, and at the same time find a ratio of electrode emission current to electrode electron emission area suitable for a large inner diameter CCFL. A topic that urgently needs a breakthrough.

Contents of the invention

In view of the above problems, the purpose of the present invention is to provide a ratio of electrode emission current and electrode electron emission area suitable for large-diameter cold cathode fluorescent lamps, so as to improve the power and luminous efficiency of cold cathode fluorescent lamps.

The present invention can be realized by adopting the following technical solutions.

A cold cathode fluorescent lamp for illumination according to the present invention includes a cold cathode fluorescent lamp tube and a driving unit. The diameter of the inner tube of the cold cathode fluorescent lamp is between 2.5mm and 30mm, and each of its 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 between 1.0mA/mm2 and 10mA/ between mm2. The driving unit is electrically connected with the electrodes of the CCFL.

In the aforementioned cold cathode fluorescent lamp for lighting, the pressure of the inert gas enclosed in the cold cathode fluorescent tube is between 1 torr and 100 torr.

The aforementioned cold cathode fluorescent light for lighting, wherein the material of the electrode is tungsten, molybdenum, niobium, nickel or alloys thereof.

In the aforementioned cold cathode fluorescent lighting, the electrodes are formed by powder metallurgy process.

The aforementioned cold cathode fluorescent lamp for lighting, wherein the luminous power of the cold cathode fluorescent tube is greater than 5W.

The aforementioned cold cathode fluorescent lamp for lighting, wherein the cold cathode fluorescent tube is a straight tube, or a U tube, or a C tube, or an annular tube, or a single helical tube, or a double helical tube.

With the above technical solution, the cold cathode fluorescent light for lighting of the present invention has at least the following advantages:

Based on the above, the present invention provides a CCFL tube with a large tube diameter. The inner tube diameter is between 2.5 mm and 30 mm, so the electrode area can be greatly increased and a higher tube current can be tolerated. It is confirmed by experiments that the present invention finds out that when the ratio of the electrode emission current to the electrode electron emission area is greater than 1.0mA/mm2, the cold cathode fluorescent lamp can start to reach high power, while the ratio of the electrode emission current to the electrode electron emission area is less than 10mA /mm2, it can avoid the oversaturation of the tube current caused by the cold cathode fluorescent tube, thereby preventing part of the power from being converted into heat, so as to improve the luminous efficiency.

Description of drawings

Fig. 1 is a schematic diagram of a cold cathode fluorescent lamp for illumination according to a preferred embodiment of the present invention.

Description of main component symbols:

1: Cold Cathode Fluorescent Lamp

11: cold cathode fluorescent tube

111: tube body

112: electrode

113: Phosphor

114: Inert gas

12: Drive unit

D1: inner tube diameter

D2: electrode diameter

Detailed ways

A cold cathode fluorescent lamp for lighting according to a preferred embodiment of the present invention will be described below with reference to related drawings.

As shown in FIG. 1 , a cold cathode fluorescent lamp 1 for illumination according to a preferred embodiment of the present invention includes a cold cathode fluorescent lamp 11 and a driving unit 12 .

The present invention does not limit the type of CCFL tube 11, which can be, for example, a straight tube, or a U tube, or a C tube, or an annular tube, or a single helical tube, or a double helical tube, and a straight tube is used as an example here. illustrate. The CCFL tube 11 includes a tube body 111 , and the inner tube diameter D1 of the tube body 111 is between 2.5mm-30mm, which belongs to the CCFL tube with a large diameter. The diameter D1 of the inner tube in this embodiment is 3mm as an example.

Two ends of the CCFL tube 11 each have an electrode 112 . The present invention does not limit the shape of the electrode 112 , which may be, for example, straight, circular, elliptical, or cup-shaped, etc. Here, a straight strip is taken as an example, and its cross section is circular. In this embodiment, the ratio of the electrode emission current of the CCFL tube 11 to the electron emission area of the electrode is between 1.0 mA/mm2˜10 mA/mm2. Wherein, the electrode emission current is the so-called "tube current". In this embodiment, the electrode emission current is 11mA-12mA as an example. The electron emission area of the electrode is calculated as the cross-sectional area of the electrode 112, and the diameter D2 of the electrode 112 is 2.6 mm (the radius is 1.3 mm). Therefore, the electrode emission current in this embodiment is 11mA, and the radius of the electrode 112 is 1.3mm to calculate, and the ratio of the electrode emission current to the electrode electron emission area can be obtained as follows:

11/(π*1.3*1.3)＝2.07(mA/mm2)

Additionally, other values may be calculated in other embodiments. For example, if the electrode diameter is 2.1mm (radius is 1.05mm), and the electrode emission current is 8mA (the calculation formula is the same as above), the ratio of the electrode emission current to the electrode electron emission area is about 2.31 (mA/mm2); The electrode diameter is 3.7mm (radius is 1.85mm), and when the electrode emission current is 27mA, the ratio of the electrode emission current to the electrode electron emission area is about 2.5 (mA/mm2).

It has been confirmed through several experiments that the present invention finds out that when the ratio of the electrode emission current to the electrode electron emission area is greater than 1.0mA/mm2 (the present embodiment is 2.07mA/mm2), the luminous power of the cold cathode fluorescent lamp 1 can begin to reach High power (such as greater than 5W), and when the ratio of the electrode emission current to the electrode electron emission area is less than 10mA/mm2, it can avoid the tube current of the cold cathode fluorescent lamp 11 from causing oversaturation, thereby preventing part of the power consumption from turning into heat, so as to improve Luminous efficiency.

The CCFL tube 11 also has a small amount of inert gas 114 (such as argon, neon) sealed therein, and the pressure of the sealed inert gas is between 1 torr-100 torr. Such a low-voltage environment helps to increase the ratio of electrode emission current to electrode electron emission area, thereby improving luminous efficiency.

In addition, the material of the electrode 112 in this embodiment can use ion bombardment-resistant materials, such as tungsten, molybdenum, niobium, nickel or alloys thereof. Since the plasma ions in the CCFL tube 11 will bombard the electrode 112 and wear the electrode, the anti-ion bombardment material can allow a higher ratio of the electrode emission current to the electrode electron emission area, thereby improving the luminous efficiency. In this embodiment, the electrode 112 is formed by powder metallurgy process.

The driving unit 12 is electrically connected to the electrode 112 of the CCFL tube 11 to drive the CCFL tube 11 to emit light. The driving unit 12 may include an inverter to provide high-voltage alternating current. The driving unit 12 can drive the cold-cathode fluorescent lamp 11 in a unilateral driving manner, or drive the CCFL tube 11 in a bilateral driving manner, and the bilateral driving manner is used as an example here.

To sum up, the present invention provides a CCFL tube with a large tube diameter. The inner tube diameter is between 2.5 mm and 30 mm, so the electrode area can be greatly increased and a higher tube current can be tolerated. It is confirmed by experiments that the present invention finds out that when the ratio of the electrode emission current to the electrode electron emission area is greater than 1.0mA/mm2, the cold cathode fluorescent lamp can start to reach high power, while the ratio of the electrode emission current to the electrode electron emission area is less than 10mA /mm2, it can avoid oversaturation of cold cathode fluorescent tubes, and then prevent part of the power from being converted into heat instead of light to improve luminous efficiency.

The above descriptions are illustrative only, not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the appended claims.

Claims (6)

1. A cold cathode fluorescent lamp for lighting, characterized in that it comprises: A cold-cathode fluorescent tube, the diameter of the inner tube is between 2.5 mm and 30 mm, each of the two ends of the cold-cathode fluorescent tube has an electrode, and the electrode emission current of the cold-cathode fluorescent tube is equal to the electron emission area of the electrode ratio between 1.0mA/mm ² and 10mA/mm ² ; and A driving unit is electrically connected with the electrodes of the CCFL. 2 . The cold cathode fluorescent lamp for illumination according to claim 1 , wherein the pressure of the inert gas enclosed in the cold cathode fluorescent lamp tube is between 1 torr and 100 torr. 3. The cold cathode fluorescent lamp for illumination according to claim 1, characterized in that the material of the electrodes is tungsten, molybdenum, niobium, nickel or alloys thereof. 4. The cold cathode fluorescent lamp for illumination according to claim 1, wherein the electrodes are formed by powder metallurgy process. 5. The cold cathode fluorescent lamp for illumination according to claim 1, characterized in that, the luminous power of the cold cathode fluorescent lamp is greater than 5W. 6. The cold cathode fluorescent lamp for lighting according to claim 1, wherein the cold cathode fluorescent lamp is a straight tube, or a U tube, or a C tube, or an annular tube, or a single helical tube, or a double helical tube .

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