KR100606236B1 - Electrodes for CCFL and a method therefor - Google Patents

Abstract

The present invention selectively coats an Al ₂ O ₃ , Y ₂ O ₃ or ZnO oxide film as a primary oxide film on the HOT electrode body cup-shaped electrode, and partially or partially coats a secondary cesium or barium oxide film on the primary oxide film. The present invention relates to a method for manufacturing an electrode body for a cold cathode fluorescent lamp having improved dark start, and to an electrode body by coating in a reverse step. The thermal balance between the electrode bodies is improved, the life span is long, and the luminance uniformity is high. A very useful electrode body for a cold cathode fluorescent lamp is disclosed which can simplify the manufacturing process.

Oxide coating, cesium oxide, cold cathode fluorescent lamp, electrode body

Description

Electrode assembly for cold cathode fluorescent lamp, and electrode assembly by the same {Electrodes for CCFL and a method therefor}             

1A is a cross-sectional view of a conventional cold cathode fluorescent lamp,

1B is an enlarged view of a surface of a conventional cold cathode fluorescent lamp cup electrode;

2 is a schematic cross-sectional view of a HOT electrode body according to an embodiment of the present invention;

3 is a schematic cross-sectional view of a HOT electrode body according to an embodiment of the present invention.

4 is a manufacturing process diagram of a cold cathode fluorescent lamp.

* Short description of drawing symbols *

51 glass tube 52 phosphor film 53 mercury, argon gas

50: electrode body 55: electrode 57: lead wire 58: sealing line

59: glass beads 60: primary coating film 70: secondary coating film

The present invention relates to an HOT or GND electrode body manufacturing method and thereby an electrode body mounted on a cold cathode fluorescent lamp which is mainly used as an LCD backlight and also recently used in special lighting such as advertising panels.

LCDs used in LCD monitors and LCD televisions of computers have a back light assembled on the back, and as a light source of the backlight, cold cathode fluorescent lamps (hereinafter referred to as 'fluorescent lamps' or 'lamps') are commonly used. This cold cathode fluorescent lamp is generally characterized by a smaller diameter compared to fluorescent lamps for general lighting, consumes less power, and has high luminance, uniformity of luminance, and long life.

The cold-cathode fluorescent lamp has the structure of FIG. 1A, in which electrode bodies 50 are sealed at both ends of a tubular glass tube 51 made of hard glass, and a phosphor film 52 coated with phosphors on an inner wall of the glass tube. ) Is formed, and as the discharge medium 53, rare gases such as argon and neon and mercury are encapsulated. The electrode body 50, which is sealed at both ends of the lamp, is connected to a cup-shaped electrode 55 made of metal such as nickel or molybdenum, neobium, and tantalum, a lead wire 57 for supplying power to the electrode, and the lead wire. It consists of a sealing line 58 penetrating the bead glass 59. The sealing line 58 penetrates through the bead glass 59, which is fused with the glass tube 51 and blocks both ends thereof, so that a KOVAR wire (Ni 29%, Co 17%, Fe 54%) or tungsten wire having a similar coefficient of linear expansion to the bead glass is formed. As the external lead wire 57, a dummet wire or a nickel wire is mainly used. In addition, the sealing line 58 forms an oxide film of a suitable thickness in advance on the surface of the metal in order to maintain airtightness with the glass beads 59, and forms the glass beads 59. In detail, the electrode portion 55 has a cup shape having a cavity, and cesium oxide (Cs ₂ O ₃ ) is applied to the surface as an electron-emitting material, and when a high voltage is applied to both electrode bodies of the lamp, the electrode surface is applied to the electric field. Electron emission occurs. The emitted electrons excite mercury, and the ultraviolet rays emitted by the mercury excitation collide with the phosphor coated inside the glass tube to finally generate visible light.

Conventional cold cathode fluorescent lamps have disadvantages such as poor dark starting and mercury dislocation such that mercury distributed inside the glass tube is moved to both electrode ends due to thermal imbalance at both ends. Therefore, a method for improving the cold cathode fluorescent lamp has been proposed. . On the other hand, the dark start is defined as the time from 24 hours after the cold cathode fluorescent lamp is stored in the dark state to the tube current after the start of the tube voltage in the dark state, when the cold cathode fluorescent lamp is stored in the dark state The electrons in the tube are completely dissipated, describing the extent to which electrons are difficult to produce without light and eventually become difficult to discharge. In addition, mercury deflection is a phenomenon caused by the temperature difference between the two ends of the glass tube, which eventually leads to a lamp failure due to mercury consumption.

The present inventors have completed the present invention by finding out the cause of the dark startup failure as a non-uniform distribution of cesium sulfide applied to the surface of the conventional electrode and devising a way to improve it. Conventionally, in order to treat the surface of the electrode body, the electrode cup portion is instantaneously dipped in cesium sulfide (Cs ₂ SO ₄ ) coating solution and dried, but the cesium sulfide is uniformly coated on the surface of the electrode cup. It was not coated. 1b shows an enlarged view of a conventional electrode body cup-shaped electrode unit, and it can be seen that cesium sulfide is unevenly coated on the surface.

An object of the present invention is to provide a method for producing an electrode body for a cold cathode fluorescent lamp with improved dark start and thereby an electrode body. Another object of the present invention is to disclose a method for manufacturing an electrode body for a cold cathode fluorescent lamp excellent in thermal equilibrium between electrode bodies and improved electrode mercury phenomenon, and thus an electrode body according to the present invention has a long life, The luminance uniformity is high, and to provide an electrode body for a cold cathode fluorescent lamp that can simplify the manufacturing process.

Cold cathode fluorescent lamp cathode (HOT) electrode body of the present invention for achieving the above object is a cylindrical or cup-shaped electrode having a cavity therein; A sealing line inserted under the electrode and connected through the bead glass; And an external lead wire connected to the sealing line. An alumina, yttrium or zinc oxide film is first applied to the surface of the HOT electrode, and all or part of the oxide film is secondly coated with cesium oxide as an electron-emitting material. On the other hand, the anode (GND) electrode body corresponding to the HOT electrode body is an electrode having a cavity therein in a cylindrical or cup shape; A sealing line inserted under the electrode and connected through the bead glass; And an external lead wire connected to the sealing line, wherein the positive electrode surface is coated with an alumina, yttrium or zinc oxide. According to the present invention, the alumina, yttrium or zinc oxide film, the cesium oxide film is formed primarily and may be coated in part or all over the surface.

In the method of manufacturing the HOT electrode body, the electrode body is cleaned and dried in a strong acid, and an Al ₂ O ₃ , Y ₂ O _3, or ZnO oxide film is used only on the cup-shaped electrode surface of the electrode body (hereinafter, typically referred to as an 'alumina oxide film'). Coating and drying and coating the cesium hydroxide coating liquid on all or part of the formed alumina oxide film and drying to form a cesium oxide film, or changing the application step to form a cesium oxide film first, and all of the cesium oxide film Alternatively, a part of the alumina oxide film may be coated and dried. Meanwhile, the GND electrode body manufacturing method may be applied in the same manner as the HOT electrode body manufacturing method, but the cesium hydroxide coating layer is not formed. Each step will be described in detail. On the other hand, the cleaning step and the alumina oxide film coating step is to be applied in common to the HOT electrode body and GND electrode body, the cesium compound coating step is a step that proceeds only to the HOT electrode body.

The washing step is performed by dipping the entire electrode body in a strong acid, preferably pH 2 strong acid, for 5 to 10 minutes. The cleaned electrode body is washed with distilled water, dried, and heat-treated at 250 ° C. for 10 minutes, followed by alumina oxide coating or cesium oxide coating. The cleaning step is useful as a preliminary step for enhancing the alumina oxide or cesium oxide coating power, but is not an essential step.

In the alumina oxide coating step, the cupping electrode part of the electrode body is instantaneously dipped in the primary coating liquid, and the electrode body having the alumina oxide film-coated electrode part is dried at 100 ° C. for at least 10 minutes. As the primary coating liquid, preferably 5% Al ₂ O ₃ (alcohol dispersion medium) is applied, or a Y ₂ O ₃ or ZnO dispersion may be selected. The entire electrode portion may be coated, but only part of the electrode portion may be partially coated up to about 3/4 from the electrode open end. After the oxide film is applied, the HOT electrode body is continuously moved to the cesium compound coating step.

The cesium compound coating step is to coat a second coating solution containing a CsOH aqueous solution and a very small amount of the wet agent on all or part of the alumina oxide film by a wet method, but preferably 5% CsOH aqueous solution centered on the alumina oxide film By using a dispersion sphere or a touch sphere (eg, a brush) filled with a secondary coating liquid containing a, it is to apply a band around the alumina oxide film. The electrode body having the cesium band forming electrode coated with the cesium hydroxide aqueous solution is dried at 100 ° C. for at least 10 minutes to complete the cesium oxide coating film. The application of the cesium compound as the secondary coating liquid is preferable when the cup-type electrode part material is nickel, but is not limited thereto. When the cup-type electrode part material is molybdenum, the coating liquid may be selected as a barium (Ba) compound. . The cesium band may be formed to be about 1/3 of the width of the oxide film centered on the central portion of the alumina oxide film, but the band width is not limited thereto. On the other hand, the cesium band may be formed in a width of about 1/3 of the width of the oxide film alone, not in the center of the alumina oxide film but also in the open portion of the electrode portion or the lower portion of the electrode portion opposite thereto.

Unlike the above, the electrode assembly for a cold cathode fluorescent lamp according to the present invention may first form a cesium oxide film and overlap the whole or part of the cesium oxide film to form an alumina oxide film as a secondary coating film. The step of forming the cesium oxide film as the primary coating film or the step of forming the alumina oxide film as the secondary coating film is carried out by the same procedure as each coating step described above, but only by changing the application sequence. Hereinafter, an alumina oxide film according to an embodiment of the present invention will be formed as a primary coating film, and a method of manufacturing a cold cathode fluorescent lamp by a secondary coating film forming step using a cesium compound will be described.

Accordingly, the HOT electrode body according to the present invention has a primary oxide film formed thereon, and has a HOT electrode portion formed with a secondary oxide film formed on the primary oxide film, and the GND electrode body has a GND electrode portion formed with a GND oxide film. do. When the primary oxide film is an alumina, yttrium or zinc oxide film, the secondary oxide film is cesium or barium oxide film. Optionally, when the primary oxide film is cesium or barium oxide film (hereinafter typically referred to as 'cesium oxide film'), the secondary oxide film Is formed of an alumina, yttrium or zinc oxide film (hereinafter typically referred to as an 'alumina oxide film'). On the other hand, the GND oxide film is composed of an alumina, yttrium or zinc oxide film. The secondary oxide film may be coated on the same surface area as the surface of the primary oxide film, or may be coated on a part of the surface of the primary oxide film, and the partial coating position is not particularly limited.

Fig. 2 shows a schematic cross-sectional view of a HOT electrode body according to the present invention, wherein a secondary oxide film, preferably Cs, is superimposed on the entire surface of the primary oxide film, preferably Al ₂ O ₃ oxide film, on the cup-shaped electrode portion. ₂ O ₃ oxide film, which is a cross-sectional view of the electrode body.

3 shows a schematic cross-sectional view of a HOT electrode body according to another embodiment of the present invention, wherein a primary oxide film, preferably an Al ₂ O ₃ oxide film, a secondary oxide film over an intermediate portion of the primary oxide film on a cup-shaped electrode portion, preferably cross-sectional view of the electrode body Cs ₂ O ₃ oxide film has been applied. As the primary oxide film, Y ₂ O ₃ or ZnO oxide film may be selectively applied, and the secondary oxide film may be selectively coated with barium oxide.

The GND electrode body electrode part matching the HOT electrode body is coated with a GND oxide film, preferably an Al ₂ O ₃ oxide film, and optionally a Y ₂ O ₃ or ZnO oxide film may be coated.

Hereinafter, the electrode body manufacturing method of the present invention will be described in more detail with reference to preferred embodiments.

1. Hot electrode body manufacturing method

The electrode body having the cup-shaped electrode part made of nickel was immersed in a strong pH 2 strong acid (trade name SemiGT) for 10 minutes, dried, washed thoroughly with distilled water, dried and heat-treated at 250 ° C. for 10 minutes. A part of the upper opening side (the part corresponding to the electrode part 3/4 from the opening) of the electrode body cup electrode part is immersed in 5% Al ₂ O ₃ coating liquid, and then pulled out to remove the coating liquid in the electrode pupil part using a wiper. Then, it was dried with lukewarm air of 35-40 ° C and 1-2 m / sec, and then heat-treated at 100 ° C for 10 minutes. Subsequently, as shown in the middle portion of the Al ₂ O ₃ oxide film layer, as shown in Figure 3, partially coated with a touch (filler) filled with a secondary coating liquid (5% CsOH aqueous solution + wet agent) at 100 ℃ The heat treatment was carried out for 10 minutes to complete the HOT electrode body having the electrode portion coated with the primary oxide film and cesium oxide film continuously. The 5% Al ₂ O ₃ coating solution was a solution in which 5% by weight of Al ₂ O ₃ powder having a particle size of 300-500 nm was dispersed in 95% by weight of ethyl alcohol and isopropyl alcohol as a dispersion medium. The 5% CsOH aqueous solution includes 5 g of CsOH and 95 g of distilled water, and the wet agent is added in an amount of 0.1 wt% based on the weight of CsOH. The wet agent is thermally decomposed at 250 ° C. as a polymer compound, and therefore does not affect cold cathode fluorescent lamp characteristics because it is used in a very small amount. The primary and secondary coating layers were coated to a thickness within 5 μm.

Meanwhile, similar to the above embodiment, various HOT electrode bodies were manufactured in the same manner using 3% and 10% CsOH aqueous solutions.

Meanwhile, a Y ₂ O ₃ or ZnO oxide film is applied using 5% Y ₂ O ₃ or 5% ZnO coating solution instead of the 5% Al ₂ O ₃ coating solution, and the cesium oxide film is deposited on the primary oxide film. Another cathode electrode body having a differentially coated electrode portion was completed.

2. Ground (GND) electrode body manufacturing method

The electrode body having a cup-shaped electrode part made of nickel was immersed in a strong pH 2 strong acid for 10 minutes, dried, washed thoroughly with distilled water, dried, and then heat-treated at 250 ° C. for 10 minutes. A part of the upper end of the electrode part (from the opening to about 3/4 spaced interval) of the electrode body is instantaneously immersed in 5% Al ₂ O ₃ , and then dried and heat-treated at 100 ° C. for 10 minutes to apply an Al ₂ O ₃ oxide film. The GND electrode body which has the prepared electrode part was completed.

By using a 5% Y ₂ O ₃ or 5% ZnO coating solution in a similar manner to the above embodiment, various GND electrode bodies having electrode portions coated with Y ₂ O ₃ or ZnO GND oxide films, respectively, were completed.

3. Assembly Example.

The HOT electrode body and the GND electrode body were fabricated in the cold cathode fluorescent lamp according to the procedure of FIG.

(1) applying phosphors to the inner surface of the glass tube with an appropriate thickness, heating, drying and firing (glass tube cutting, washing, coating, neck cleaning, baking), (2) inserting a hot electrode body on one side of the glass tube to prevent it from falling off. Pinching (mounting and sealing), inserting the ground electrode body and then completely sealing (mounting and sealing primary) step, (3) mercury is injected into the hot side as a getter-type (mercury injection), and the inside is vacuumed. Making (exhaust), (4) encapsulating a suitable pressure of argon, neon or a mixture of gas, forcibly diffusing mercury into the glass tube (primary mercury diffusion), and hermetically sealing by a burner, (5 A cold cathode fluorescent lamp was assembled by reducing blackened lead wire during the cutting and sealing of unnecessary parts, and diffusing the mercury evenly inside the glass tube (secondary mercury diffusion).

Experimental Example 1.

The characteristics of the cold cathode fluorescent lamp (temperature measurement, starting voltage, dark starting time) applying the electrode bodies prepared in the above example were measured to obtain the following results.

GND electrode part coated with Al ₂ O ₃ oxide Electrode condition Temperature measurement result (℃) Starting voltage (V) Dark start-up time (ms) HOT GND HOT CENTER GND H / G deviation Cleaning: Al ₂ O ₃ : CsOH (3%) Al2O3 125.0 54.9 115.1 -9.9 795 21 Cleaning: Al ₂ O ₃ : CsOH (5%) Al2O3 127.9 55.9 118.2 -9.7 788 9 Cleaning: Al ₂ O ₃ : CsOH (10%) Al2O3 123.1 55.4 115.9 -7.7 793 14

Comparative Experiment

Electrode condition Temperature measurement result (℃) Starting voltage (V) Dark start-up time (ms) HOT GND HOT CENTER GND H / G deviation Cs2SO4 application No treatment 90.1 58.2 122.5 32.5 781 300

As a result of measuring the lamp characteristics by mounting the cold cathode fluorescent lamp electrode body according to the present invention, the desirable characteristics of the lamp, that is, the dark starting time is maintained at 30 ms or less, and the hot electrode temperature is at least 0-10 ° C than the GND electrode temperature. As a result, it was possible to manufacture a lamp that could solve the mercury dislocation problem during mounting. On the other hand, although not shown, in the case of the electrode to which the HOT electrode oxide film is applied Y ₂ O ₃ or ZnO similar to Table 1, the dark start, the temperature deviation characteristics improved compared to the comparative example, the applicable results.

Experimental Example 2.

On the other hand, by applying the same HOT electrode unit electrode body and GND electrode electrode body coated with a ZnO oxide film as in Experimental Example 1, the lamp characteristics were measured to obtain the results shown in Table 2.

GND electrode part coated with ZnO oxide Electrode condition Temperature measurement result (℃) Starting voltage (V) Dark start-up time (ms) HOT GND HOT CENTER GND H / G deviation Cleaning: Al ₂ O ₃ : CsOH (3%) ZnO 128.4 64.2 120.9 -8.4 790 15 Cleaning: Al ₂ O ₃ : CsOH (5%) ZnO 130.0 63.4 123.7 -6.3 794 18 Cleaning: Al ₂ O ₃ : CsOH (10%) ZnO 121.5 65.3 113.0 -8.5 792 15

As a result of measuring lamp characteristics by mounting a cold cathode fluorescent lamp electrode body according to the present invention, in particular, a GND electrode part coated with a ZnO oxide film, the desirable characteristics of the above-mentioned lamp, that is, dark startup time, is maintained at 30 ms or less, Since the hot electrode temperature is at least 0-10 ℃ higher than the GND electrode temperature, the lamp can be manufactured to solve the problem of mercury dislocation during mounting. On the other hand, although not shown, in the case of the HOT electrode in which the primary oxide film of the HOT electrode part is applied with Y ₂ O ₃ or ZnO, the dark starting and temperature deviation characteristics of the HOT electrode part are similar to those of the comparative example. .

Experimental Example 3.

On the other hand, by applying the same HOT electrode unit electrode body and Y ₂ O ₃ oxide film-coated GND electrode electrode body as in Experimental Example 1, the lamp characteristics were measured to obtain the results shown in Table 3.

GND electrode part coated with Y ₂ O ₃ oxide film Electrode condition Temperature measurement result (℃) Starting voltage (V) Dark start-up time (ms) HOT GND HOT CENTER GND H / G deviation Cleaning: Al ₂ O ₃ : CsOH (3%) Y ₂ O ₃ 120.4 63.3 114.0 -6.4 788 16 Cleaning: Al ₂ O ₃ : CsOH (5%) Y ₂ O ₃ 121.0 65.3 115.7 -5.3 791 16 Cleaning: Al ₂ O ₃ : CsOH (10%) Y ₂ O ₃ 118.5 62.8 109.0 -9.5 790 19

As a result of measuring the lamp characteristics by mounting the Y ₂ O ₃ oxide coated GND electrode part, the dark starting time is kept below 30ms, and the hot electrode temperature is at least 0-10 ℃ higher than the GND electrode temperature. It was possible to manufacture a lamp that can solve the problem. On the other hand, in the case of the electrode to which the HOT electrode portion primary oxide film is applied Y ₂ O ₃ or ZnO similarly to Table 3, the dark start, temperature deviation characteristics improved compared to the comparative example, the applicable results.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

The present invention selectively coats an Al ₂ O ₃ , Y ₂ O _3, or ZnO oxide film as a primary oxide film on a cup electrode portion of the cathode electrode body, and preferably all or part of a secondary cesium oxide film on the primary oxide film. The present invention discloses a method for manufacturing an electrode body for a cold cathode fluorescent lamp having improved dark startup, or an electrode body according to the above, by applying or reversing the coating order. According to the technical configuration, thermal equilibrium between electrodes can be achieved. The present invention proposes a method for manufacturing an electrode body for a cold cathode fluorescent lamp and a electrode body according to the above-mentioned phenomenon, and has a long lifetime, high luminance uniformity, and a very useful cold process which can simplify the manufacturing process. An electrode body for a cathode fluorescent lamp is disclosed.

Claims (8)

Applying an alumina, yttrium or zinc oxide film to the cup-shaped electrode surface of the cleaned electrode body; A method of manufacturing an electrode assembly for a cold cathode fluorescent lamp comprising the step of applying a cesium or barium compound to all or part of the surface of the oxide film by a wet method. Applying a cesium or barium compound by a wet method to the cup-shaped electrode surface of the cleaned electrode body; And applying an alumina, yttrium or zinc oxide film to all or part of the surface of the coating film. A method of manufacturing an electrode assembly for a cold cathode fluorescent lamp comprising the step of applying an alumina, yttrium or zinc oxide film to the surface of the cup-shaped electrode portion of the cleaned electrode body. The method of claim 1, wherein the applying of the alumina, yttrium or zinc oxide film is performed by dipping the electrode part in a coating liquid in which Al ₂ O ₃ , Y ₂ O ₃ or ZnO powder is dispersed in an alcohol medium. Electrode assembly method for cold cathode fluorescent lamps. The method of claim 1, wherein the applying of the cesium compound is performed by dipping an electrode portion coated with alumina, yttrium or zinc oxide in a CsOH aqueous solution, or spraying or contacting a CsOH aqueous solution with a portion of the electrode coated with the oxide film. The electrode body manufacturing method for a cold cathode fluorescent lamp characterized by the above-mentioned. The cold cathode fluorescent lamp electrode assembly according to claim 1, further comprising a step of cleaning the electrode assembly for a cold cathode fluorescent lamp including a cup-shaped electrode part in a strong acid before the alumina, yttrium or zinc oxide film coating step. An electrode body for a cold cathode fluorescent lamp produced by claim 1. An electrode assembly for cold cathode fluorescent lamps prepared by claim 3.

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