KR100935276B1 - Electrode material - Google Patents

Abstract

The present invention relates to a cold cathode fluorescent lamp comprising a glass tube having a phosphor layer on an inner wall surface, sealed with rare gas and mercury therein, and a pair of electrodes disposed at both ends in the glass tube, wherein Ti, 0.001 mass in total of at least one element selected from Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Be, Si, Al, Y, Mg, In and rare earth elements The electrode is made of a Ni alloy containing not less than 5.0% by mass and not more than 5.0%, and the balance of Ni and impurities. By using an electrode made of Ni alloy having the above composition instead of nickel, it is possible to improve discharge resistance, oxidation resistance, sputtering resistance, and reaction resistance with mercury, and to realize high brightness and long life. will be.

Description

Electrode Material {ELECTRODE MATERIAL}

1 is a cross-sectional view showing a schematic configuration of a cold cathode fluorescent lamp.

The present invention relates to an electrode material suitable for an electrode of a cold cathode fluorescent lamp, a manufacturing method for producing an electrode for cold cathode fluorescent lamps using the electrode material, and a cold cathode fluorescent lamp. In particular, it relates to a cold cathode fluorescent lamp of higher brightness and long life.

Conventionally, cold-cathode fluorescent lamps are often used as various light sources, such as light sources for image irradiation of image scanners, and backlight sources of liquid crystal display devices (liquid crystal displays) such as liquid crystal monitors of PCs and liquid crystal TVs. See Japanese Patent Application Laid-Open No. 2004-71276 and Japanese Patent Application Laid-open No. Hei 10-144255. As a cold cathode fluorescent lamp, there exists a thing of the structure shown in FIG. 1, for example. 1 is an example of a cold cathode fluorescent lamp, and is a sectional view showing a schematic configuration thereof. The cold cathode fluorescent lamp 100 has a phosphor layer 101 on an inner wall surface, a glass tube 102 in which rare gas and mercury are sealed, and a pair of electrodes 103 disposed in the glass tube 102. . The phosphor layer 101 is formed over almost the entire circumference and the entire length of the inner wall surface of the glass tube 102, and mainly between the two electrodes 103 in the tube 102 becomes a light emitting portion, and the vicinity of the electrode 103. This non-light emitting part becomes. The electrode 103 is a cup shape having one end opening, the other end having a bottom, and disposed in the glass tube 102 so that the openings face each other (Japanese Patent Application Laid-Open No. 2004-71276, Japanese Patent Laid-Open No. 10-144255). Publication). A lead wire (outer wire 104) is connected to the other end side (bottom side) of the electrode 103 that is not open, and a voltage is applied to the electrode 103 via the lead wire 104. An inner lead wire 105 made of a material such as Kovar, which is adjusted to a thermal expansion coefficient approximately equal to that of the glass tube 102, is connected between the electrode 103 and the outer lead wire 104. A bead glass 106 is welded to the outer circumference of the inner lead wire 105. By fixing the electrode 103 to the glass tube 102 and sealing the tube 102 by the bead glass 106, the airtight state in the tube 102 is stabilized and maintained. There is also a fluorescent lamp that does not contain mercury in which only rare gas is sealed in the glass tube 102.

The fluorescent lamp 100 emits light according to the following principle. When a high voltage is applied between the two electrodes 103 via the lead wire 104, electrons slightly present in the glass tube 102 are attracted to the electrode 103 at high speed and collide with each other. Secondary electrons are emitted and discharged. By this discharge, electrons attracted to the anode and mercury molecules present in the glass tube 102 collide with each other to emit ultraviolet rays. The ultraviolet rays excite the phosphors, and the phosphors emit visible light.

Nickel (Ni) is typical as a material for forming the electrode. Japanese Unexamined Patent Application Publication No. 2004-71276 discloses using Ti, Zr, Hf, Nb or Ta, and Japanese Unexamined Patent Application Publication No. 2004-207056 uses Mo, Nb, and Ta as the material for forming the electrode. It is.

In recent years, in the backlight unit used for a liquid crystal display etc., thinness, light weight, high brightness, and long life are important. For this reason, further miniaturization, high brightness, and long life are strongly demanded for cold cathode fluorescent lamps used as backlight light sources. In addition, high speed, long life, and the like are important in image scanners, and high luminance and long life are strongly demanded for cold cathode fluorescent lamps as light sources.

In a conventional cold cathode fluorescent lamp having an electrode made of nickel, mercury ions generated by discharge impinge upon the electrode during lighting, so that a phenomenon called sputtering occurs in which electrode material scatters in the glass tube and deposits on the inner wall of the tube. If sputtering occurs, the electrode is consumed. In particular, only a portion of the electrode is intensively consumed, leaving holes in the portion, which renders the electrode unusable for discharging, thereby extending the life of the fluorescent lamp. In addition, the sputtering layer (layer made of evaporated electrode material) and mercury form amalgam. For such reasons, if the lamp is turned on for a long time, mercury is almost absorbed by the sputtering layer, so that radiation of ultraviolet rays is not sufficiently performed, the brightness of the lamp is extremely lowered, and the lifetime of the fluorescent lamp is reached. That is, in the conventional cold cathode fluorescent lamp having an electrode made of nickel, the life is relatively shortened by the sputtering.

If the shape of an electrode is made into a cylindrical shape with a bottom, sputtering can be suppressed to some extent by the hollow cathode effect, but it cannot be said that it is sufficient structure for the request of further high brightness and long lifetime. Although it is considered to increase the lamp current for the demand for higher luminance, the increase in the current increases the electrode load, so that sputtering easily occurs, that is, the sputtering speed is increased. As a result, consumption of the electrode and formation of amalgam are promoted, resulting in a decrease in the lifetime of the fluorescent lamp. If the electrode is enlarged, the problem caused by sputtering can be reduced, but in such a case, there is a problem that 1. the thickness and the size are reduced, and 2. the non-light emitting portion is increased.

On the other hand, as described in Japanese Patent Application Laid-Open No. 2004-71276 or Japanese Patent Application Laid-Open No. 2004-207056, a material other than nickel is used for the electrode material, or a layer made of a material other than nickel is formed on the body made of nickel. It is contemplated to suppress sputtering. However, a material such as Mo, Nb, Ta, or the like is difficult to be processed to the electrode, or even if it can be processed to the electrode, there is a problem that the electrode made of this material is difficult to be joined to an inner lead wire or the like. In addition, materials such as Mo, Nb, and Ta listed in Japanese Patent Laid-Open No. 2004-71276 and Japanese Patent Laid-Open No. 2004-207056 are relatively expensive, and use of an electrode made of this material leads to considerable cost increase. .

On the other hand, it is proposed to apply a substance which promotes electron emission to the electrode, for example, a lanthanum compound, a cesium compound, a yttrium compound, a barium compound and the like. However, these electron-emitting materials are scattered due to the collision of ions generated by the discharge during lamp lighting, which makes it difficult to further extend the lifespan.

The main object of the present invention is to provide an electrode material which can contribute to the long life and high luminance of a cold cathode fluorescent lamp. Another object of the present invention is to provide a method for producing an electrode for cold cathode fluorescent lamps, which is suitable for obtaining a bottomed cylindrical electrode from this electrode material. Further, another object of the present invention is to provide a cold cathode fluorescent lamp having a longer lifetime and high brightness.

In order to obtain a cold cathode fluorescent lamp having a higher brightness and a longer lifetime, the present inventors earnestly examined the constituent members of the lamp, with particular attention on the electrodes. The characteristics required as an electrode for realizing a high-brightness, long-life cold cathode fluorescent lamp are: 1. easy to discharge, 2. difficult to oxidize the electrode surface, 3. difficult to form mercury and amalgam, 4 We found that the sputtering speed was slow.

When the electrode is difficult to discharge, as a result of less electrons being emitted, ultraviolet light is not sufficiently emitted and it is difficult to increase the luminance. On the other hand, since the electrode which is easy to discharge is easy to make high brightness, when using at the same brightness | luminance as the electrode which is hard to discharge, it can be made longer life. In addition, since the electrode which is easy to discharge can emit electrons at lower power, the power consumption can be reduced. Therefore, the electrode is required to be made of a material which is easy to discharge.

Moreover, when an oxide film exists on an electrode surface, discharge property is impaired. That is, the electrode becomes difficult to discharge. Here, the electrode material or the electrode may be heated when the electrode is manufactured or when the fluorescent lamp is manufactured using the obtained electrode (such as when the electrode and the inner lead wire are joined). When the electrode material easily adsorbs oxygen gas, an oxide film is easily formed on the surface of the electrode by this heating. On the other hand, in the electrode which consists of electrode materials which are hard to adsorb oxygen gas, an oxide film is hard to form on the surface, and the fall of discharge property can be reduced. Therefore, the electrode is required to be made of a material which is difficult to adsorb oxygen gas.

In addition, if the electrode material easily forms mercury and amalgam, the electrode made of this electrode material promotes the consumption of mercury when sputtering, and consequently shortens the lifetime of the fluorescent lamp. On the other hand, the electrode which consists of electrode materials which are hard to form amalgam can slow the consumption of mercury, and can prolong life. Therefore, it is preferable that an electrode consists of a material which is hard to form amalgam.

In addition, when the electrode is easy to cause sputtering, that is, the sputtering speed is high, the consumption of the electrode is promoted, and consequently, the life of the fluorescent lamp is shortened. On the other hand, since the electrode which is hard to produce sputtering hardly forms a sputtering layer in a glass tube, since the fall of a brightness | luminance is reduced, it is high brightness over a long time compared with the electrode which is easy to produce sputtering. Therefore, the electrode is required to be made of a material which is less likely to cause sputtering, that is, a slower sputtering rate.

In addition to the above characteristics, the present inventors have studied electrode materials (components) that do not use expensive materials such as Mo, Nb or the like in order to achieve a lower cost. As a result, knowledge has been obtained that a Ni alloy using Ni which is relatively inexpensive is preferable as a component of the electrode material. Therefore, the electrode material of the present invention is made of Ni alloy.

Specific electrode materials are electrode materials used for electrodes of cold cathode fluorescent lamps, and Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Be, Si, Al, At least 1 element selected from the reference group which consists of Y, Mg, In, and a rare earth element contains 0.001 mass% or more and 5.0 mass% or less in total, and remainder consists of Ni and an impurity. That is, this electrode material is characterized by being composed of a Ni alloy containing a specific additive element in a specific range. An electrode made of an electrode material made of such a Ni alloy having a specific composition is easy to discharge and has a slow sputtering rate. Moreover, in the electrode which consists of this electrode material, an oxide film is hard to form and it is difficult to form amalgam. Therefore, by using the electrode made of the electrode material of the present invention, it is possible to obtain a cold cathode fluorescent lamp of high brightness and long life.

Another electrode material is an electrode material used for the electrode of a cold cathode fluorescent lamp, and consists of Ni alloy, and has a work function less than 4.7 eV. The work function is the minimum energy required to release one electron from the solid surface in vacuum. The smaller the work function is, the easier the electron is to be released, that is, the easier to discharge the material. The present inventors have found that less than 4.7 eV is desirable as a result of evaluating the discharge characteristic required for the electrode of the cold cathode fluorescent lamp with a work function. Based on this knowledge, this electrode material is comprised from Ni alloy and satisfy | fills a specific work function. By using an electrode made of such an electrode material, a cold cathode fluorescent lamp of high brightness and long life can be obtained.

Another electrode material is an electrode material used for the electrode of a cold cathode fluorescent lamp, and consists of Ni alloy, and the etching rate is less than 22 nm / min. When the electrode sputters, the portion where the atoms are released by the collision of mercury ions in the electrode causes erosion and the surface becomes rough. As the electrode is more likely to cause sputtering, the depth of erosion per hour increases. Using the average depth of erosion per hour as the etching rate, the present inventors have found that less than 22 nm / min is preferable as a result of evaluating the sputtering state required for the electrode of the cold cathode fluorescent lamp with the etching rate. Based on this knowledge, this electrode material is comprised from Ni alloy and satisfy | fills a specific etching rate. By using an electrode made of such an electrode material, a cold cathode fluorescent lamp of high brightness and long life can be obtained. In addition, an etching rate has the meaning substantially the same as a sputtering rate, and an etching rate is used in this invention.

Hereinafter, the present invention will be described in more detail.

The electrode material of the present invention is made of Ni alloy. In particular, as the additive element, a reference group consisting of Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Be, Si, Al, Y, Mg, In, and rare earth elements At least one element selected from is preferred. The additional element may be one kind of element selected from the above reference group, or two or more kinds of elements. As for content of an additional element, 0.001 mass% or more and 5.0 mass% or less are preferable. When using Ni alloy containing several types of additional elements, it adjusts so that total content may satisfy the said range. If the content of the added element is less than 0.01% by mass, the effect of improving the characteristics such as higher luminance and longer lifetime due to the addition of the added element cannot be obtained. On the other hand, this characteristic improvement effect tends to improve with an increase in the content of the added element, but it is considered that the content of the added element is saturated at 5.0% by mass. Moreover, when content of an additional element exceeds 5.0 mass%, the cost will increase by the increase of an additional element. In addition, the increase of the additive element lowers the plastic working property when producing the electrode material or when producing the electrode with the electrode material. As described later, the electrode material of the present invention is produced by performing a plastic working, such as rolling or drawing, on a casting material after melt casting. In the case of producing an electrode using the electrode material of the present invention, plastic working such as press working or forging described later is performed on the electrode material. Therefore, the upper limit of the content of the additive element is set to 5.0% by mass in order not to lower the plastic workability of the material for producing the electrode material or the electrode material.

The reference group is a first group consisting of Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Mg, In and Be, Si, Al, Y, rare earth elements It is classified into the 2nd group which consists of 2, and the element contained in either group may be added element. In particular, in the case where at least one element selected from the first group (hereinafter referred to as element I) is an additional element, the content is 0.001 mass% or more and 2.0 mass% or less. That is, the electrode material of the present invention contains at least one element selected from the first group in a total of 0.001% by mass or more and 2.0% by mass or less, and the balance can be made of Ni and impurities. By constituting the electrode material with the Ni alloy containing the element I in this range, it is possible to obtain an electrode having the characteristics of 1 to 4 described above at a lower cost. Further, the cast material made of this Ni alloy has workability to the extent that plastic processing such as rolling processing or drawing processing can be carried out, and the above plastic processing can be performed to produce an electrode material. Moreover, since this electrode material has sufficient workability to the extent that plastic processing, such as press working and forging processing, can be performed, the above plastic processing can be performed to produce an electrode. Element 1 may be one kind of element, or two or more kinds of elements may be sufficient as it. When element I is made into several types of elements, it adjusts so that total content may be 0.001-2.0 mass%, and adds to Ni. If the content of element I is less than 0.01% by mass, the effect of improving the characteristics due to the inclusion of element I cannot be obtained. On the other hand, this characteristic improvement effect tends to saturate content of element I to 2.0 mass%. Moreover, when element I is added in excess of 2.0 mass%, there exists a possibility of raising manufacturing cost or reducing plastic workability. In view of the manufacturing cost and plastic workability, the content of Element I is preferably 2.0 mass% or less. More preferable elements as the element I are Mg, Ti, Hf, Ti and Zr, Hf and Zr. In particular, addition of Mg has the effect of improving the plastic workability of the cast material. More preferable content of element I is 0.01 mass% or more and 1.0 mass% or less in total. By further reducing the added element, the cost of the electrode material can be reduced.

Although at least one element selected from the second group (hereinafter referred to as element II) may be an additional element, the element I and element II in the specific range may be combined to form an additional element. In the latter case, content of element II is 0.001 mass% or more and 3.0 mass% or less. That is, the electrode material of the present invention contains 0.001 to 2.0 mass% of one or more elements selected from the first group in total, and 0.001 to 3.0 mass% in total of one or more elements selected from the second group. It may contain below and remainder may consist of Ni and an impurity. In addition to element I, an electrode material is comprised by Ni alloy containing 0.001-3.0 mass% of element II, and the electrode manufactured from this electrode material can improve discharge resistance, oxidation resistance, and sputtering resistance more. . Moreover, even if it contains 0.001-3.0 mass% of element II, it hardly affects the plastic workability of an electrode material. This element II may be one kind of element, or two or more kinds of elements may be sufficient as it. When element II is made into several types of elements, it adjusts so that total content may be 0.001-3.0 mass%, and adds to Ni. When content of element II is less than 0.01 mass%, the effect by containing element II cannot be acquired. On the other hand, this effect tends to saturate content of element II to 3.0 mass%, and when it adds exceeding 3.0 mass%, there exists a possibility that a cost increase and the plastic workability of an electrode material may fall. Therefore, in consideration of manufacturing cost and plastic workability, the content of element II is preferably 3.0 mass% or less. More preferable elements as element II are Si, Al, and Y. In particular, when Y is used as an additive element, the precipitates are present in the grain boundaries, whereby growth and oxidation of the crystal grains upon heating can be prevented. More preferable content of element II is 0.01 mass% or more and 2.0 mass% or less in total. By further reducing the added element, the cost of the electrode material can be reduced.

As Ni alloy which added element II, Ni-Y alloy is mentioned, for example. When Y which is easy to oxidize is added to Ni, it is difficult to uniformly contain an appropriate amount of Y in Ni, or it tends to deteriorate the plastic workability of the Ni alloy. Therefore, when Y is used as an additive element, it is preferable to add Si and Mg within the above ranges for the purpose of removing oxygen and suppressing deterioration of plastic workability. Moreover, in addition to addition of Si and Mg, it is preferable to adjust content of C to a specific range as mentioned later. As the electrode material of the present invention, such a Ni-Y alloy or a Ni-Y-based alloy can be used.

The Ni alloy which is the metal constituting the electrode material of the present invention is, for example, pure Ni (99.0% by mass or more of Ni and impurities) as the main component Ni, and the reference group, the first group and the first group It is good to obtain by adding the element chosen from 2 groups. Commercially available pure Ni may be used. Commercially available pure Ni (more than 99% by mass of Ni) contains C or S as impurities. The inventors of the present invention have found that the electrode containing more than 0.1% by mass of C and S in total causes a decrease in luminance and lifespan. In addition, while the strength of the electrode material with a large amount of C increased, the plastic workability decreased, and the electrode material with a large amount of S was embrittled. Therefore, it is preferable that content of C and S of the electrode material of this invention is 0.10 mass% or less in total. On the other hand, if the C or S content is less than 0.001% by mass, the strength of the electrode material may be insufficient, or the grains of Ni alloy constituting the electrode material may be coarsened, which may adversely affect the press workability and the forging workability. There is. Therefore, it is preferable that Ni alloy contains 0.001 mass% or more of C and S in total. In order to make content of C and S into 0.001 mass% or more and 0.1 mass% or less in total, Ni which has little content of C and S is used, or what is reduced by refining is mentioned.

The electrode material of the present invention made of Ni alloy has a work function of less than 4.7 eV and is excellent in discharge characteristics. Therefore, the electrode which consists of electrode material of this invention is easy to discharge, and implement | achieves high brightness. In addition, when the electrode made of the electrode material of the present invention is used at the same brightness as a conventional electrode, the life can be further extended, and high luminance can be obtained with a smaller current, thereby reducing power consumption. can do. The work function can be changed by appropriately adjusting the type and content of the added element added to the Ni alloy. When content of the said additional element becomes large, a work function will become small easily. In addition, the smaller the work function, the higher the luminance of the electrode tends to be. More preferable work function is 4.3 eV or less, and still more preferable work function is 4.0 eV or less. The work function can be measured by, for example, ultraviolet photoelectron spectroscopy.

Moreover, the electrode material of this invention which consists of Ni alloys has an etching rate less than 22 nm / min, and is excellent in sputtering resistance. Therefore, since the electrode which consists of electrode material of this invention is hard to sputter | spatter, the fall of a brightness | luminance is small even if it uses for a long time, and long life is achieved. In the case where the electrode made of the electrode material of the present invention is used to have the same lifetime as a conventional electrode, since the electrode made of the electrode material of the present invention is hardly sputtered, the state of high luminance can be maintained for a long time and high luminance is achieved. To realize. Moreover, since it is hard to sputter | spatter, in the case of the electrode which consists of this invention electrode material, when a brightness | luminance is raised by a large electric current, a sputtering layer is hard to form, and the fall of a brightness | luminance and a fall of a lifetime can be reduced. The etching rate can be changed by appropriately adjusting the type and content of the added element added to the Ni alloy. When content of the said additional element increases, an etching rate will become small easily. In addition, the smaller the etching rate, the longer the service life tends to be. More preferable etching rate is 20 nm / min or less, still more preferable etching rate is 18 nm / min or less, and especially preferable etching rate is 16 nm / min or less. An etching rate is measured as follows. The electrode material was placed in a vacuum apparatus, ion irradiation of inert elements was carried out for a predetermined time, the surface roughness of the electrode material after irradiation was measured, and the value obtained by dividing the surface roughness by the irradiation time (surface roughness / irradiation time) was determined by the etching rate. do.

The electrode material of the present invention may be a plate-like material or a linear material (wire). The plate-like material is obtained by, for example, melting → casting → hot rolling → cold rolling and heat treatment. The linear phase material is obtained by, for example, melting → casting → hot rolling → cold drawing and heat treatment. More specifically, Ni and the additive element of the main component, in particular, an element selected from any one of the reference group, the first group, and the second group are prepared, and these are dissolved in a vacuum melting furnace, an atmospheric melting furnace, or the like to form the Ni alloy. Get a melt. Adjust the molten metal appropriately (for example, in case of melting by vacuum melting furnace, temperature adjustment, or in case of melting by atmospheric melting furnace, removing or reducing impurities or inclusions by refining, etc., or adjusting temperature). Or ingot) by casting called vacuum casting. In the case where the electrode material of the present invention is used as a plate-like material, the ingot is hot rolled to obtain a rolled plate material. Cold rolling and heat treatment are repeatedly performed on this rolled sheet material to obtain a plate-shaped electrode material of the present invention. On the other hand, when the electrode material of the present invention is used as a linear material, the ingot is hot rolled to obtain a rolled wire rod. Cold drawn wire and heat treatment are repeatedly performed on the rolled wire to obtain a linear electrode material of the present invention. Even if the electrode material of the present invention is either a plate material or a linear material, the final heat treatment (annealing) is carried out at 700 to 1000 ° C, especially at 800 to 900 ° C, under a hydrogen atmosphere or a nitrogen atmosphere. desirable.

It is preferable that content of hydrogen contained in the electrode material of this invention obtained as mentioned above is 0.1 ppm or more and 20 ppm or less by mass ratio. When the hydrogen content of the electrode material is more than 20 ppm by mass ratio, the electrode obtained by the electrode material is likely to be brittle at the junction portion with the inner lead wire, causing a decrease in the bonding strength, or a source of generating the impurity gas by the electrode. The impurity gas is generated in the lamp, which leads to a decrease in the life of the lamp. On the other hand, when hydrogen content is less than 0.1 ppm by mass ratio, when welding the inner lead wire which consists of a cobar etc. to the electrode which consists of this electrode material, an electrode will become oxidatively discolored easily. More preferable hydrogen content is 1 ppm or more and 10 ppm or less by mass ratio. In order to make hydrogen content of an electrode material into 0.1 ppm or more and 20 ppm or less by mass ratio, the atmosphere of the said final heat processing at the time of manufacture of the said electrode material is mentioned, for example. For example, when setting the atmosphere of the final heat treatment as a hydrogen atmosphere, it is possible to adjust the hydrogen content or to set the atmosphere to other than hydrogen such as a nitrogen atmosphere. The electrode material subjected to final heat treatment in a nitrogen atmosphere or an electrode made of the electrode material has a hydrogen content of 100 ppm or less in terms of mass ratio.

Moreover, when the inventors investigated, when the crystal grain of the alloy which comprises an electrode material is minute, the knowledge which is effective in extending the lifetime and high brightness of the electrode which consists of this electrode material was acquired. Specifically, the average crystal grain size is preferably 70 µm or less. More preferable average grain size is 50 micrometers or less, More preferably, it is 20 micrometers or less. The average grain size of the alloy constituting the electrode material can be adjusted by adjusting the type and content of the added element or by the final heat treatment conditions at the time of producing the electrode material. For example, in the final heat treatment, when the heating temperature (heat treatment temperature) is set to a relatively high temperature and the heating time is shortened, it is possible to prevent the growth of particles. Specifically, the heat treatment temperature is 700 to 1000 ° C., especially about 800 ° C., and in the case of a plate material, the moving speed is 50 ° C./sec or more, and in the case of a linear material, the line speed is 50 ° C./sec or more. It can be mentioned. If the moving speed or the line speed is increased, the average grain size tends to decrease. When the electrode is manufactured using an electrode material having an average grain size of 70 µm or less, the grain size of the Ni alloy constituting the electrode slightly changes due to press working, forging processing, or joining of the inner lead wire. However, the grain size of the electrode is basically dependent on the grain size of the electrode material, so that the average grain size is generally 70 µm or less.

In the case where the electrode material of the present invention is used as a plate-shaped material, a cup-shaped electrode can be produced simply by pressing the plate-shaped material into a predetermined shape. When a cup-shaped electrode is produced by press working, waste portions are formed in the plate-like material, so that the yield is lowered, and thus high cost is likely to occur. However, since a conventional electrode manufacturing apparatus (press apparatus) can be used, the cost can be reduced by reducing the equipment cost.

On the other hand, when the electrode material of the present invention is used as a linear material (wire), an electrode of a rod-shaped body or a cup-shaped electrode can be easily obtained. In the former case, a rod-shaped electrode can be manufactured by cutting a wire to a predetermined length. In the latter case, a cup-shaped electrode can be manufactured by cutting a wire into a short length material having a predetermined length, and forging the short material to form a cylindrical shape with a bottom. The electrode material of the present invention is made of Ni alloy, and in addition to achieving high brightness and long life, as described above, the reduction of plastic workability due to additional elements is suppressed, and the forging is relatively strong ( Vi) Plastic processing of processing can be performed sufficiently. Thus, since the electrode material of the linear invention of the present invention can be manufactured by cutting or forging, even if one of the rod-shaped electrode and the cup-shaped electrode is manufactured, since the scrapped portion hardly occurs, the yield is high. It is favorable, and the manufacturing cost of an electrode can be reduced. In the case of producing a cup-shaped electrode by forging the linear electrode material of the present invention, it is possible to simplify the thickness of the bottom portion in comparison with the thickness of the side portion. When the bottom portion has a thick electrode, the bonding strength between the bottom surface of the electrode and the inner lead wire made of a cobar can be further increased, and a high quality fluorescent lamp can be provided. In order to prevent the lack of bonding strength when joining the electrode bottom surface and the inner lead wire by welding or the like, it is effective to make the thickness of the electrode bottom portion thicker than the electrode side portion. In general, when the thickness of the bottom portion of the electrode is about four times the thickness of the side portion, it is effective to obtain sufficient bonding strength. In the case of forming a cup-shaped electrode by press-processing a plate-like material, there is a limit to thickening only the bottom portion, and at most, twice the thickness of the side portion is the limit. On the other hand, when forging a linear body (forging material) and manufacturing a cup-shaped electrode, it is easy to thicken only the electrode bottom part more than twice. Therefore, in the case of using a linear electrode material, the quality of the lamp can be further improved in addition to the improvement of yield and cost reduction at the time of electrode production.

By providing an electrode made of Ni alloy having the specific composition, a cold cathode fluorescent lamp having a higher brightness and a longer lifetime can be obtained. That is, a glass tube having a phosphor layer on an inner wall surface and sealed with rare gas and mercury therein, or a glass tube having a phosphor layer on an inner wall surface and sealed with a rare gas therein, and an electrode disposed at an end in the tube. Cathode fluorescent lamp, wherein the electrode is made of Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Be, Si, Al, Y, Mg, In, rare earth elements A fluorescent lamp containing at least one element selected from the group and not more than 0.001% by mass and not more than 5.0% by mass in total, and the balance consisting of Ni and impurities realizes high luminance and long life. In particular, if the electrode has a cup shape having one end opening and the other end having a bottom, the sputtering resistance can be improved by the hollow cathode effect. This cup-shaped electrode can be obtained simply by pressing or forging the electrode material of the present invention as described above. A pair of cup-shaped electrodes may be prepared, and a fluorescent lamp may be disposed in the glass tube so that the openings of the two electrodes face each other. Alternatively, a cup lamp may be prepared and disposed only at one end of the glass tube. do.

The electrode comprises 1. Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Mg, In total of at least one element selected from the first group consisting of It contains 0.001 mass% or more and 2.0 mass% or less, remainder consists of Ni and an impurity, 2. 0.001-2.0 mass% of 1 or more types of elements chosen from the said 1st group in total, and Be, Si, Al Or 1 or more elements selected from the second group consisting of Y and rare earth elements may be included in an amount of 0.001 to 3.0% by mass or less, and the balance may be made of Ni and impurities.

The electrode made of the Ni alloy having the above-mentioned specific composition and the electrode material of the present invention are excellent in oxidation resistance, and an oxide film is hardly formed at the time of electrode production or bonding with an inner lead wire. Specifically, the thickness of the oxide film formed on the surface of the electrode can be 1 µm or less. Therefore, this electrode has little discharge deterioration, and can achieve high brightness and long life of a lamp. More preferable thickness of the oxide film is 0.3 µm or less. In the case of an electrode made of a Ni alloy containing Ti, Zr, and Hf as an additive element, an oxide film is particularly hard to be formed, and the thickness thereof can be 0.3 m or less. The easy formation of the oxide film affects the composition of the alloy constituting the electrode, and in the case of the electrode formed of the Ni alloy of the specific composition, the thickness of the oxide film is 1 µm or less. In addition, by performing heat treatment in an atmosphere other than oxygen at the time of manufacturing the electrode material, it is possible to prevent the formation of an oxide film on the electrode material.

The electrode material of the present invention made of Ni alloy satisfies the discharge resistance and sputtering resistance required for an electrode of a cold cathode fluorescent lamp. In particular, the electrode material of the present invention made of a specific composition of Ni alloy is sufficiently provided with discharge resistance, oxidation resistance, resistance to mercury, and sputtering resistance required for an electrode of a cold cathode fluorescent lamp. For this reason, the cold cathode fluorescent lamp of the present invention having an electrode made of the electrode material of the present invention or an electrode made of the above-mentioned specific Ni alloy can realize further higher brightness and longer life without increasing the size of the electrode. have.

In addition, the electrode material of the present invention is excellent in plastic working properties such as press working and forging processing in addition to the characteristics required for the electrodes. In particular, by forging the linear electrode material of the present invention, a cup-shaped electrode excellent in sputtering resistance can be easily produced at low cost.

The electrode material of this invention can be used suitably for the electrode of a cold cathode fluorescent lamp. Moreover, the manufacturing method of the electrode of this invention can be used suitably for manufacture of the cup-shaped cold cathode fluorescent lamp electrode from the linear electrode material of this invention. The fluorescent lamp of the present invention is, for example, a light source for a backlight of a liquid crystal display, a light source for a front light of a small display, a light source for irradiation of documents such as a copying machine or a scanner, and a light source for various power devices such as a rubber eraser light source for a copying machine. It can be used suitably as a.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. The electrode for cold cathode fluorescent lamps was produced using Ni alloy of the component composition (metal No.1-36) shown in Table 1, 2. The electrode was produced from electrode materials having two different shapes. Specifically, a linear electrode material and a plate electrode material were prepared. A cup-shaped electrode was produced by forging the linear electrode material, and a cup-shaped electrode was produced by pressing the plate-shaped electrode material.

<Linear electrode material>

까지 가공하고, 압연선재를 얻었다. 이 압연선재에 냉간신선 및 열처리를 조합해서 실시하고, 얻어진 선재에 최종열처리(연화처리)를 실시해서, 선직경 1.6㎜

의 풀림재를 얻었다. 연화처리는, 온도를 800℃, 선속을 10~150℃/sec의 범위에서 적절히 선택하고, 질소분위기 또는 수소분위기로 해서 실시하였다(표 3~6에 나타낸 시료 중, 수소함유량이 10ppm이하의 시료가 질소분위기). 또, 주성분으로 한 Ni는, 시판의 순Ni(99.0질량%이상 Ni)를 이용하여, 정련상태를 변화함으로서, C 및 S의 합계 함유량을 변화시켰다(이 점은, 후술하는 판형상의 전극재료도 마찬가지임).The linear electrode material was produced as follows. The molten metal of the component composition shown in Tables 1 and 2 was produced using the normal vacuum melting furnace, and the ingot was obtained by vacuum casting by adjusting melt temperature suitably. Hot-rolled the obtained ingot, 5.5 mm wire diameter

It processed to and obtained the rolled wire. Cold rolled wire and heat treatment were combined with this rolled wire, and the final wire was subjected to final heat treatment (softening), and the wire diameter was 1.6 mm.

Obtained the loosening material. The softening treatment was performed by appropriately selecting the temperature in the range of 800 ° C. and the line speed in the range of 10 to 150 ° C./sec and using a nitrogen atmosphere or a hydrogen atmosphere (samples having a hydrogen content of 10 ppm or less in the samples shown in Tables 3 to 6). Nitrogen atmosphere). In addition, Ni as a main component used the commercially available pure Ni (99.0 mass% or more Ni), and changed the total content of C and S by changing the refining state (this point also the plate-shaped electrode material mentioned later also The same is true).

<Plate-shaped electrode material>

The plate-shaped electrode material was produced as follows. Ingots were prepared from the molten metal of the component compositions shown in Tables 1 and 2 by the same method as the linear electrode material. Hot rolling was performed to the obtained ingot, and the rolled sheet material of thickness 4.2mm was obtained. After heat-treating this rolled board material, the surface was cut and the process board material of thickness 4.0mm was obtained. Cold rolling and heat treatment were repeatedly performed on this treated plate material, and final heat treatment (softening treatment) was performed on the obtained plate material to obtain a plate-shaped loosening material having a thickness of 0.2 mm. The softening treatment was appropriately selected in a temperature range of 800 ° C. and a moving speed in the range of 10 to 150 ° C./sec.

800㎛ 타원형, 분석깊이: 약 1㎚로 해서 측정하였다. 에칭율은, 경면 연마한 풀림재에 진공장치 내에서 아르곤 이온을 조사한 후, 표면거칠기를 측정하고, 조사시간과 표면거칠기로부터 구하였다. 전처리로서, 풀림재에 부분적으로 마스킹을 실시하고 나서 이온조사를 실시하였다. 이온조사는, X선광전자분광분석장치(PHI 제품 Quantum-2000)를 이용하여, 가속전압: 4kV, 이온종: Ar⁺, 조사시간: 120min, 진공도: 2×10^-8~4×10^-8torr(2.7×10^-9~5.3×10^-9kPa), 아르곤압: 약 15mPa, 입사각도: 시료면에 대해서 약 45도로 해서 실시하였다. 표면거칠기의 측정은, 촉침식 표면형상측정기(Vecco사 제품 Dektak-3030)를 이용하여, 촉침: 다이아몬드 반경 = 5㎛, 침압: 20mg, 주사거리: 2㎜, 주사속도: Medium으로 해서 실시하였다. 풀림재에 있어서 이온조사에 의해 표면에 침식이 생긴 개소(마스킹되어 있지 않은 개소)에 대해서 침식의 평균깊이를 표면거칠기로 하고, 표면거칠기/조사시간(120min)을 에칭율로 하였다.About the obtained linear annealing material and plate-shaped annealing material, hydrogen content (mass ratio ppm), the average crystal grain size (micrometer), work function (eV), and etching rate (nm / min) of the metal which comprise an annealing material are measured. It was. The results are shown in Tables 3 to 6. Tables 3 and 4 are samples using linear electrode materials, and Tables 5 and 6 are samples using plate-shaped electrode materials. The hydrogen content was measured by the melting-thermal conductivity method in an inert gas (measurement apparatus: EMGA-620 by Horiba Seisakusho). The average crystal grain size of the metal was measured in accordance with the method shown in JIS G 0551. The work function was measured by ultraviolet photoelectron spectroscopy. Specifically, after performing Ar ion etching for several minutes as a pretreatment, using a compound electron spectroscopic analyzer (UV-150HI attached to ESCA-5800 made by PHI), an ultraviolet source: He I (21.22eV) / 8 W, at the time of measurement Degree of vacuum: 3 x 10 ^-9 to 6 x 10 ^-9 torr (O.4 x 10 ^-9 to 0.8 x 10 ^-9 kpa), base vacuum before measurement: 4 x 10 ^-10 torr (5.3 x 10- ^{) 11} kPa), applied bias: approx. -10V, energy resolution: 0.13eV, analysis area:

800 micrometers elliptical, Analysis depth: It measured as about 1 nm. The etching rate was determined by irradiating argon ions to the mirror polished annealing material in a vacuum apparatus and measuring the surface roughness from the irradiation time and the surface roughness. As a pretreatment, the unwinding material was partially masked, followed by ion irradiation. The ion irradiation was carried out using an X-ray photoelectron spectroscopy device (Quantum-2000 manufactured by PHI), and the acceleration voltage was 4 kV, the ion species was Ar ⁺ , the irradiation time was 120 min, and the vacuum degree was 2 x 10 ^-8 to 4 x 10 ^-8. torr (2.7 x 10 ^-9 to 5.3 x 10 ^-9 kPa), argon pressure: about 15 mPa, incident angle: about 45 degrees with respect to the sample surface. The surface roughness was measured using a stylus type surface shape measuring instrument (Dektak-3030, manufactured by Vecco) as stylus: diamond radius = 5 µm, needle pressure: 20 mg, scanning distance: 2 mm, and scanning speed: Medium. The mean depth of the erosion was set to the surface roughness at the place where the erosion occurred on the surface by the ion irradiation in the annealed material (surface roughness / irradiation time (120 min)) as the etching rate.

, 길이 3.0㎜, 개구부의 직경 1.4㎜

, 개구부의 깊이 2.6㎜, 바닥부분의 두께 0.4㎜)을 얻을 수 있었다.Next, the obtained linear loosening material was cut to a predetermined length (1.0 mm), and cold forging was performed on the obtained forging material to prepare a cup-shaped electrode. As a result, an annealing material or a cup-shaped electrode (outer diameter 1.6 mm) having a certain composition

, Length 3.0 mm, opening 1.4 mm

, The depth of the opening of 2.6 mm and the thickness of the bottom part of 0.4 mm) were obtained.

, 길이 3.0㎜, 개구부의 직경 1.4㎜

, 개구부의 깊이 2.8㎜, 바닥부분의 두께 0.2㎜)을 얻을 수 있었다.Moreover, the obtained plate-shaped loosening material was cut | disconnected to predetermined | prescribed magnitude | size (100 mm angle), cold press processing was performed to the obtained plate-like piece, and the cup-shaped electrode was produced. As a result, an annealing material or a cup-shaped electrode (outer diameter 1.6 mm) having a certain composition

, Length 3.0 mm, opening 1.4 mm

, The depth of the opening part 2.8 mm, and the thickness of the bottom part 0.2 mm) were obtained.

In the obtained electrode, the thickness (micrometer) of the oxide film of the metal which comprises an electrode was measured. The results are shown in Tables 3 to 6 (Tables 3 and 4: Samples using linear electrode materials, and Tables 5 and 6: Samples using plate-shaped electrode materials). The thickness of the oxide film was cut | disconnected and the electrode surface was measured and calculated | required by Auger electron spectroscopy. Moreover, about the obtained electrode, hydrogen content and average crystal grain diameter were measured similarly to the above, and it was almost the same as the case of an annealing material.

Next, the cold cathode fluorescent lamp as shown in FIG. 1 was produced using the obtained electrode. Specifically, it produced in the following procedure. An inner lead wire made of a cobar and an outer lead wire made of a copper clad Ni alloy wire are welded, the inner lead wire is welded to the bottom of the electrode, and the bead glass is welded to the outer circumference of the inner lead wire. Two such electrode members are prepared. In addition, a glass tube having a phosphor layer (halophosphate phosphor layer in this test) on the inner wall surface is prepared, and one electrode member is inserted into one end of the opened tube, and the bead glass and the tube are welded. Thus, one end of the tube is sealed and the electrode member is fixed in the tube. Next, a rare gas (Ar gas in this test) and mercury are introduce | transduced from the other end of the open glass tube, and similarly, the other electrode member is fixed and a glass tube is sealed. By this procedure, a cold cathode fluorescent lamp is arranged so that the openings of the pair of electrodes face each other. For each electrode of each composition, the pair of electrode members are produced, and a cold cathode fluorescent lamp is produced using these electrode members. These fluorescent lamps were examined for luminance and lifetime. In this test, sample Nos. 50A and 50B having a nickel-made electrode had a central luminance (43000 cd / m 2) and a lifetime of 100. The samples Nos. 1A to 38A and 1B to 38B were used. The luminance and lifespan are relatively shown. The results are shown in Tables 3 to 6. In addition, the life was made when the central luminance became 50%.

As shown in Tables 3 and 4, the fluorescent lamps of Sample Nos. 1A to 38A with electrodes made of Ni alloy had higher luminance and longer lifetime than the fluorescent lamps of Sample No. 50A with electrodes made of nickel. to be. In addition, as shown in Tables 5 and 6, the fluorescent lamps of Sample Nos. 1B to 38B with electrodes made of Ni alloy had higher luminance than the fluorescent lamps of Sample No. 50B with electrodes made of nickel. Long life. This is considered to be because the metal Nos. 1 to 36 are materials having a low work function and etching rate, that is, a material that is easy to discharge and have a slow sputtering rate, compared to the metal No. 50 of the nickel single substance. In addition, metal Nos. 1 to 36 made of Ni alloy are difficult to deteriorate discharge characteristics because they are less likely to form an oxide film, and are less likely to form mercury and amalgam, as compared with nickel No. 50 of single metal. It is feed.

In the fluorescent lamps of Sample Nos. 1A to 38A and 1B to 38B, a Ni alloy having a reduced hydrogen content by performing a softening treatment under a nitrogen atmosphere, specifically, an electrode made of a Ni alloy having a hydrogen content of 10 ppm or less at a mass ratio. One fluorescent lamp had a longer lifetime and higher brightness. Moreover, the average crystal grain size of Ni alloy was 70 micrometer or less in the sample which made the ship speed or the moving speed into 50 degreeC / sec or more. In the fluorescent lamps of Sample Nos. 1A to 38A and 1B to 38B, the fluorescent lamp including the electrode made of a Ni alloy having an average grain size of 70 µm or less had a longer lifetime and higher luminance. In addition, among the fluorescent lamps of Sample Nos. 1A to 38A and 1B to 38B, the fluorescent lamp including the electrode made of Ni alloy having a total content of C and S of 0.001 to 0.1% by mass was longer life and high brightness.

The electrode made of the Ni alloy having the above-mentioned specific composition and the electrode material of the present invention are excellent in oxidation resistance, and an oxide film is hardly formed at the time of electrode production or bonding with an inner lead wire. Specifically, the thickness of the oxide film formed on the surface of the electrode can be 1 µm or less. Therefore, this electrode has little discharge deterioration, and can achieve high brightness and long life of a lamp. More preferable thickness of the oxide film is 0.3 µm or less. In the case of an electrode made of a Ni alloy containing Ti, Zr, and Hf as an additional element, an oxide film is particularly hard to be formed, and the thickness thereof can be 0.3 m or less. The easy formation of the oxide film affects the composition of the alloy constituting the electrode, and in the case of the electrode formed of the Ni alloy of the specific composition, the thickness of the oxide film is 1 µm or less. In addition, by performing heat treatment in an atmosphere other than oxygen at the time of manufacturing the electrode material, it is possible to prevent the formation of an oxide film on the electrode material.

The electrode material of the present invention made of Ni alloy satisfies the discharge resistance and sputtering resistance required for an electrode of a cold cathode fluorescent lamp. In particular, the electrode material of the present invention made of a specific composition of Ni alloy is sufficiently provided with discharge resistance, oxidation resistance, resistance to mercury, and sputtering resistance required for an electrode of a cold cathode fluorescent lamp. For this reason, the cold cathode fluorescent lamp of the present invention having an electrode made of the electrode material of the present invention or an electrode made of the above-mentioned specific Ni alloy can realize further higher brightness and longer life without increasing the size of the electrode. have.

In addition, the electrode material of the present invention is excellent in plastic working properties such as press working and forging processing in addition to the characteristics required for the electrodes. In particular, by forging the linear electrode material of the present invention, a cup-shaped electrode excellent in sputtering resistance can be easily produced at low cost.

The electrode material of this invention can be used suitably for the electrode of a cold cathode fluorescent lamp. Moreover, the manufacturing method of the electrode of this invention can be used suitably for manufacture of the cup-shaped cold cathode fluorescent lamp electrode from the linear electrode material of this invention. The fluorescent lamp of the present invention is, for example, a light source for a backlight of a liquid crystal display, a light source for a front light of a small display, a light source for irradiation of documents such as a copying machine or a scanner, and a light source for various power devices such as a rubber eraser light source for a copying machine. It can be used suitably as a.

Claims (18)

0.001% by mass or more and 2.0% by mass in total of at least one element selected from the first group consisting of Ti, Hf, Zr, V, Fe, Nb, Mo, Mn, W, Sr, Ba, B, Th, Mg, In It contains less than%, 0.001% by mass or more and 3.0% by mass or less of a total of at least one element selected from the second group consisting of Be, Si, Al, Y, and rare earth elements (excluding Y), The balance consists of Ni and impurities, An electrode material, which is used for an electrode of a cold cathode fluorescent lamp. The method of claim 1, An electrode material comprising 0.01% by mass or more and 1.0% by mass or less in total of the elements selected from the first group, and 0.01% by mass or more and 2.0% by mass or less in total of the elements selected from the second group. The method according to claim 1 or 2, An electrode material containing Y. The method according to claim 1 or 2, An electrode material, characterized in that the work function is 1.5 eV or more and less than 4.7 eV. The method according to claim 1 or 2, An electrode material, characterized in that the etching rate exceeds 0 and is less than 22 nm / min. The method according to claim 1 or 2, Electrode material characterized by the sum total of C and S being 0.001 mass% or more and 0.10 mass% or less. The method according to claim 1 or 2, An electrode material, characterized in that the hydrogen content is 0.1ppm or more and 20ppm or less. The method according to claim 1 or 2, An electrode material, characterized in that the average crystal grain size of the metal constituting the electrode material is more than 0 and 70 mu m or less. The method according to claim 1 or 2, The electrode material is an electrode material, characterized in that the plate-like material. The method according to claim 1 or 2, The electrode material is an electrode material, characterized in that the linear material. Cutting the linear phase material of the electrode material according to claim 10 to obtain a short length material of a predetermined length; And a step of forging the forging material, forming the bottomed cylindrical shape to obtain an electrode, and manufacturing an electrode for a cold cathode fluorescent lamp. It is formed by the electrode material of Claim 1 or 2, An electrode, which is used for a cold cathode fluorescent lamp. An electrode according to claim 12, An inner lead wire connected to the bottom surface of the electrode, an outer lead wire connected to the inner lead wire, An electrode member, comprising: bead glass welded to an outer circumferential portion of the inner lead wire. A glass tube having a phosphor layer on an inner wall surface and sealed with a rare gas, mercury or a rare gas therein; The electrode member of Claim 13 fixed to the edge part of the said glass tube is provided, A cold cathode fluorescent lamp, wherein the glass tube and the bead glass of the electrode member are welded to seal the glass tube and the electrode is fixed to an end portion in the glass tube. delete delete delete delete

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