JP2011040356A - Discharge lamp and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp having high durability when a beadless electrode mount is used and a method for manufacturing the same.
[Solution]
In the discharge lamp of the present invention, an electrode mount 3 having an electrode 31 and an inner lead 32 is sealed at the end of the glass bulb 1, and the electrode mount 3 is a bead on which no beads are formed around the inner lead 32. The shape of the sealing part 12 on the inner side of the glass bulb 1 is a concave or convex shape, and the concave or convex shape in the tube axis direction When the length is L, −0.3 mm ≦ L ≦ 1.5 mm (provided that the convex is positive) is satisfied. Further, a peroxide layer 321 is formed on the surface of the inner lead 32, and at least a part of the peroxide layer 321 is located in the sealing portion 12.
[Selection] Figure 2

Description

  The present invention relates to a discharge lamp used for a light source of a backlight of a liquid crystal television or a notebook computer and a method for manufacturing the same.

  Currently, cold cathode discharge lamps are the mainstream of light sources used for backlights. The cold cathode discharge lamp has a structure in which an electrode mount made of an electrode, an inner lead or the like is sealed at the end of a glass bulb. As this electrode mount, as in Patent Documents 1 to 4, it is common to use an electrode mount with beads in which glass balls (hereinafter referred to as beads) are formed around the inner leads.

JP 2003-151438 A JP 2003-229060 A JP 2004-335245 A Japanese Patent No. 4185539

  Since these beads are important members in terms of lamp strength and manufacturing, they have been indispensable in the past. Recently, however, a discharge lamp cannot be realized without using beads to reduce the number of parts. Is being studied.

  However, when beads are not used, problems such as cracking and peeling due to weak impact and damage due to thermal expansion have occurred, resulting in lower durability than conventional lamps. The lamp could not be realized.

  An object of the present invention is to provide a discharge lamp having a high durability when a beadless electrode mount is used, and a method for manufacturing the same.

  In order to achieve the above object, a discharge lamp of the present invention is a discharge lamp in which an electrode mount having an electrode and an inner lead is sealed at an end of a bulb, and the electrode mount has beads around the inner lead. A beadless electrode mount that is not formed, and the shape of the sealing portion where the electrode mount is sealed is a concave or convex shape, and the concave or convex tube When the length in the axial direction is L, −0.3 mm ≦ L ≦ 1.5 mm (provided that the convex is positive) is satisfied.

  Further, the discharge lamp manufacturing method of the present invention is a discharge lamp manufacturing method in which an electrode mount having an electrode and an inner lead is sealed at an end of a bulb, wherein beads are not formed around the inner lead. An electrode mount disposing step of positioning the electrode mount on the valve at a planned sealing portion of the valve; a valve heating step of heating the planned sealing portion to contact the valve with the inner lead; and the inner lead And an electrode mount moving step of moving relative to the valve on the center side of the valve in the tube axis direction.

  ADVANTAGE OF THE INVENTION According to this invention, when a beadless electrode mount is used, a discharge lamp with high durability and its manufacturing method can be provided.

The figure for demonstrating the discharge lamp manufactured by the manufacturing method of the discharge lamp of the 1st Embodiment of this invention. The figure for demonstrating the range of X enclosed with the dashed-dotted line of FIG. The figure for demonstrating the manufacturing method of the discharge lamp of this Embodiment. The figure for demonstrating the discharge lamp of a comparative example. The figure for demonstrating the result of the thermal shock test of the discharge lamp of Example 1, a comparative example, and a prior art example. The figure for demonstrating evaluation of the discharge lamp of Example 1, Example 2, a comparative example, and a prior art example. The figure for demonstrating the discharge lamp of Example 3. FIG. The figure for demonstrating the discharge lamp of Example 4. FIG. The figure for demonstrating the peeling rate of the discharge lamp of Example 1, Example 3, Example 4, and a comparative example. The figure for demonstrating the discharge lamp of the 2nd Embodiment of this invention. The figure for demonstrating the manufacturing method of the discharge lamp of the 3rd Embodiment of this invention.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a discharge lamp manufactured by a discharge lamp manufacturing method according to a first embodiment of the present invention.

  The discharge lamp according to the embodiment of the present invention is a cold cathode fluorescent lamp, and includes a glass bulb 1 made of hard glass or soft glass as a main part. The glass bulb 1 is an elongated glass having a cylindrical portion 11 at the center and sealing portions 12 at both ends, and a discharge space 111 is formed inside the glass bulb 1. In the discharge space 111, a discharge medium made of mercury and a rare gas is enclosed. As the rare gas, a simple substance such as neon, argon, xenon, krypton, or a mixed gas can be used. On the inner surface of the glass bulb 1, a phosphor layer 2 made of RGB three-wavelength phosphor is formed in a range covering at least the light emission region of the lamp.

  The electrode mount 3 is sealed to the sealing portion 12. The electrode mount 3 is a so-called beadless type electrode mount that does not have glass beads as can be seen from the figure, and includes an electrode 31, an inner lead 32, and an outer lead 33.

  The electrode 31 has a bottomed opening shape (cup shape) having a bottom portion and a side portion, and is disposed opposite to both sides of the discharge space 111 so that the opening is on the center side of the glass bulb 1. As the electrode 31, for example, a metal that is difficult to be sputtered such as nickel, molybdenum, tungsten, niobium, tantalum, titanium, rhenium, or the like can be used.

The inner lead 32 is sealed to the sealing part 12, and one end thereof is led out to the discharge space 111 and joined to the bottom part of the electrode 31 by welding. As the inner lead 32, it is desirable to use a material within ± 10 × 10 ⁻⁷ / ° C. with ^respect to the thermal expansion coefficient of the glass bulb 1. Examples of this include kovar (alloys containing nickel, iron, cobalt, etc.), iron-nickel alloys, molybdenum, tungsten, etc. In the present invention, iron is deposited on the surface of kovar, iron-nickel alloys, etc. It is particularly desirable to use materials.

  The outer lead 33 is made of, for example, jumet, and is joined to the inner lead 32 led out of the glass bulb 1 by welding so as to extend in the external space direction along the lamp axis.

  Here, the configuration in the vicinity of the sealing portion of the discharge lamp of the present embodiment will be described in more detail with reference to FIG. 2A and 2B are diagrams for explaining the range of X surrounded by the alternate long and short dash line in FIG. 1, wherein FIG. 2A is an external view and FIG. 2B is a cross-sectional view. In FIG. 2A and the subsequent external views, the inner leads 321 in the vicinity of the sealing portion 12 are expanded or contracted because they are illustrated taking into consideration the influence of the lens effect due to glass.

  As can be seen from the figure, the sealing portion 12 has a configuration in which there is no bead inside and the glass bulb 1 is directly sealed to the inner lead 32. The inner shape is almost flat, and the glass is sealed so that the glass is substantially perpendicular to the inner lead 32. Therefore, even if the glass expands due to heat, stress concentrates on the part. It has a difficult shape. Further, a peroxide layer 321 is formed on the surface of the inner lead 32 on the valve end side, and a part thereof is sealed to the sealing portion 12. This peroxide layer 321 improves the sealing property with glass. The peroxide layer 321 is an oxide layer that appears to be blackened visually, and has a diffusion concentration of 15% to 50%. The diffusion concentration is a relative value of the iron concentration at the start of diffusion when the detected iron concentration in the inner lead is 100%, and can be adjusted according to conditions such as the heating temperature and heating time of the inner lead 32. is there.

  Next, a manufacturing method of the discharge lamp as shown in FIG. 2, particularly the sealing step of the electrode mount 3 on the sealing side (1st side) will be described in detail with reference to FIG.

  First, as shown in (a), the glass bulb 1 with the phosphor layer 2 formed on the inner surface is disposed so that the tube axis is substantially perpendicular to the ground, and the electrode mount 3 is mounted on the glass bulb 1. An electrode mount placement process is performed at the lower end, the glass bulb 1 is fixed by the fixing member 4, and the electrode mount 3 is supported by the push-up means 5. Here, the electrode mount 3 disposed in the glass bulb 1 in this step is a metal generated by heat during the manufacturing process such as when the inner lead 32 and the electrode 31 or the outer lead 33 are joined by a method such as hydrogen reduction. It is a so-called reduction-treated electrode mount from which oxygen components on the surface are removed.

  Next, as shown in (b), the sealing portion 13 which is a bulb portion covering a part of the inner lead 32 and the outer lead 33 is heated by the burner 6, and the glass A part of the inner lead 32 is brought into contact with the inner lead 32 to perform a valve heating step for forming the sealing portion 12. And in this Embodiment, the peroxide layer formation process is performed continuously to a valve | bulb heating process. That is, after the sealing part 12 is formed, the inner lead 32 protruding to the outside of the sealing part 12 is heated by the burner 6 to form the peroxide layer 321 on the surface.

  When the peroxide layer 321 is formed on the surface of the inner lead 32, the burner 6 is separated from the glass bulb 1, and as shown in FIG. The electrode mount moving step of lifting the outer lead 33 upward is performed by moving. By this electrode mount moving step, the glass in the vicinity of the inner lead 32 moves to the center side in the tube axis direction, the shape of the sealing portion 12 is corrected, and the peroxide layer 321 outside the sealing portion 12 is corrected. Is pushed into the inside of the sealing part 12, so that a discharge lamp is formed in which the inner shape of the sealing part 32 is substantially flat and the peroxide layer 321 exists in the sealing part 12 as shown in FIG. be able to.

  Whether or not a lamp has been manufactured by the above method can be confirmed by observing the presence or absence of beads, the shape of the inside of the sealing portion 12, the presence or absence of the peroxide layer 321 in the sealing portion 12, and the like.

  An example of the discharge lamp according to the present embodiment is shown below.

Example 1
Glass bulb 1; soft glass, total length = 833.5 mm, outer diameter = 4.0 mm, inner diameter = 3.0 mm, wall thickness = 0.5 mm, thermal expansion coefficient = 92 × 10 ⁻⁷ / ° C.
Discharge medium; mixed gas of mercury, 80% neon and 20% argon = 30 torr,
Phosphor layer 2; composed of RGB phosphors;
Electrode 31: Made of nickel, tube axial length = 10 mm, bottom thickness = 0.12 mm, outer diameter = 2.7 mm, inner diameter = 2.5 mm cup shape,
Inner lead 32; 52 alloy (nickel = 52%, iron = 48% alloy), diameter = 0.8 mm, thermal expansion coefficient = 98 × 10 ⁻⁷ / ° C.,
Peroxide layer 321; diffusion distance = 2.4 μm, diffusion concentration = 31.6%,
Outer lead 33; made of Jumet, diameter = 0.6mm,
Sealing length L1 = 1.484 mm, electrode-sealing portion distance L2 = 0.722 mm, internal shape of sealing portion 32 = flat.

  The lamp of this example (Example 1), a discharge lamp (Comparative Example) in which the process of (d) is not performed after the process of FIG. 3 (c) as shown in FIG. 4, and a conventional discharge with beads A thermal shock test was performed on the lamp (conventional example). The result is shown in FIG. In this thermal shock test, the lamp was immersed in a solder bath (270 ° C. to 430 ° C.) for about 1 mm from the end of the tube for 1 second, and the state was maintained in the solder bath for 5 seconds, then taken out from the solder bath. This is a test in which cracks are inspected with a glow inspection / microscope after performing 1 to 5 cycles of natural cooling at room temperature as one cycle.

  As can be seen from FIG. 5, in Example 1, cracks hardly occur even at a high temperature of 430 ° C., whereas cracks occurred in the conventional example at 300 ° C. and in the comparative example at 360 ° C. Yes. From this result, it can be seen that the example is much more resistant to thermal shock than the conventional example and the comparative example.

  Further, the outer lead 33 is gradually pulled strongly outward in the tube axis direction with the glass bulb 1 fixed, and it is confirmed whether or not the inner lead 32 and the glass are peeled until the tensile strength reaches 15 kgf. As a result of the tensile strength test, it was found that Example 1 was about 7%, the conventional example was about 44%, and the comparative examples were all peeled off. From this result, it can be seen that Example 1 has high tensile strength.

  From the above, in the manufacturing process, the electrode mount moving process and the peroxide layer forming process are performed to improve the sealing part shape and to place the peroxide in the sealing part, making it much more durable than the conventional and comparative examples. It can be seen that a high discharge lamp can be realized.

  Next, the vertical direction of Example 1 and the lamp (Example 2) in which the electrode mount 3 that has been subjected to a mild oxidation process (pre-oxidation) to the extent that the surface of the inner lead 32 is not blackened after the reduction process is sealed. A vertical strength test was conducted on the strength of the test piece. Note that the strength in the vertical direction is such that the glass bulb 1 is fixed in a state where the outer lead 33 is bent substantially vertically, a load in the vertical direction is applied to the outer lead 33 with respect to the tube axis of the lamp, and the sealing portion 12 is damaged. This is the value of the push-pull gauge.

  As a result, the vertical strength of Example 1 was 3.09 kgf, and Example 2 was 3.58 kgf. From this, it can be seen that a discharge lamp with higher strength can be realized by performing both peroxidation and pre-oxidation. Incidentally, since the comparative example was 1.00 kgf and the conventional example was 3.41 kgf, it can be said that both Example 1 and Example 2 are sufficiently practical.

  Next, a lighting life test was performed on these lamps. As a result, the life characteristics of Example 1 and the conventional example were good, but the leak occurred in the comparative example. On the other hand, in Example 2, phenomena such as the lamp voltage changing during the life and the unevenness of mercury were observed. This is considered to be because an oxide layer was brought into the discharge space 111 by pre-oxidation.

  When the durability and life characteristics of each lamp are evaluated from the above tests, the result is as shown in FIG. In other words, considering durability, life characteristics, cost and process, in the case of a beadless electrode mount, Example 1 was the best, Example 2 was good, and Comparative Example was not possible.

(Example 3)
7A and 7B are diagrams for explaining the discharge lamp of Example 3, wherein FIG. 7A is an external view, and FIG. 7B is a cross-sectional view. About each part of subsequent embodiment, the same part as each part of 1st Embodiment is shown with the same code | symbol, and the description is abbreviate | omitted.

  In Example 3, the inner shape of the sealing portion 12 is a concave shape. Specifically, a gap-shaped recess 121 is formed along the inner lead 32. The length L in the tube axis direction is −0.1 mm, which is shorter than the length L in the tube axis direction of the conventional example in FIG. The length L of the concave portion 121 in the tube axis direction is a distance from a contact point between the inner lead 32 and the glass to a portion where the lens effect of the inner lead 32 almost disappears. In addition, the peroxide layer 321 is present in the sealing portion 12, but the formation length in the tube axis direction is shorter than that in the first embodiment.

  The shape as in the third embodiment can be formed by pushing it up shorter than in the first embodiment in the process of FIG.

Example 4
FIGS. 8A and 8B are diagrams for explaining the discharge lamp of Example 4, FIG. 8A is an external view, and FIG. 8B is a cross-sectional view.

  In Example 4, the inner shape of the sealing portion 12 is a convex shape. Specifically, a hemispherical convex portion 122 is formed on the sealing portion 12 so as to protrude into the discharge space 111. The length L in the tube axis direction is 0.6 mm. Further, the peroxide layer 321 is present in the sealing portion 12, but the formation length in the tube axis direction is longer than that in the first embodiment, and in this lamp, up to a part in the convex portion 122. Existing.

  The shape as in the fourth embodiment can be formed by pushing the distance D longer than that in the first embodiment in the process of FIG.

  Next, a tensile strength test was performed on the lamps of Example 1, Example 3, Example 4, and the conventional example. The result is shown in FIG.

  From FIG. 9, it can be seen that the tensile strength is highest in Example 1, that is, the case where the shape of the sealing portion is flat, and the tensile strength decreases as the length of the concave portion or convex portion in the tube axis direction increases. Moreover, it turns out that the shape inside the sealing part 12 from the inclination of the peeling rate is desirable in order of flat shape, convex shape, and concave shape. From this result, it is found that the inner shape of the sealing portion 12 is sufficient if the tube axis length L of the concave or convex shape is in the range of −1.0 mm ≦ L ≦ 1.5 mm. As a result, the strength could be maintained.

  Further, when the thermal shock test was performed on the lamps of Example 1, Example 3, Example 4, and the conventional example, the flat state was the most resistant to the thermal shock as in the above-described tensile test. . In the case of the convex shape, it was almost the same as the case of the flat shape, and it was found that the thermal shock resistance did not decrease so much even if the length L in the tube axis direction was increased. On the other hand, it has been found that in the case of the concave shape, it becomes extremely weak against thermal shock, and particularly when the length L in the tube axis direction is longer than 0.3 mm, cracks are likely to occur even at low temperatures. From this result, the inner shape of the sealing portion 12 has the result that the sufficient thermal shock resistance can be maintained if the tube-shaped length L of the concave shape is not larger than 0.3 mm. .

  From the above, the shape inside the bulb of the sealing portion 12 to which the inner lead 32 is sealed is a concave or convex shape in which the tube axis length L is −0.3 mm ≦ L ≦ 1.5 mm. Is desirable. Further, when −0.2 mm ≦ L ≦ 1.0 mm, and further −0.1 mm ≦ L ≦ 0.5 mm, a highly reliable discharge lamp can be realized.

  As long as the peroxide layer 321 is present in the sealing portion 12 as much as possible, the durability, particularly the tensile strength, is significantly improved as compared with the case where it does not exist, and the presence range in the sealing portion 12 is larger. It has been confirmed that durability is improved. Therefore, at least a part of the peroxide layer 321 is preferably present in the sealing portion 12, and further, the longer the length in the tube axis direction, the better. However, if the peroxide layer 321 exists in the discharge space 111 beyond the sealing portion 12, there is a concern about the influence of slow leak and the like, in addition to the lamp voltage change, mercury bias, and so on. It is desirable that the width of the sealant does not exceed the inner end side of the sealing portion 12.

  Here, the length of the peroxide layer 321 in the sealing portion 12 is a relative position between the opening end of the glass bulb 1 and the inner lead 32 in FIG. 3A, and is located outside the sealing portion 12 in FIG. Adjustment is possible by the length of the inner lead 32 to be adjusted, the push-up distance D of the electrode mount 3 in (d), and the like.

The present invention is not limited to the combination of the materials of the above-described embodiments. For example, the glass bulb 1 has a thermal expansion coefficient of about 51 × 10 ⁻⁷ / ° C., and the inner lead 32 has a thermal expansion coefficient of about 52. It has been confirmed that the same effect can be obtained even when Kovar having × 10 ⁻⁷ / ° C. is used.

  Therefore, in the present embodiment, when the shape of the sealing portion 12 on the inner side of the glass bulb 1 is a concave or convex shape, and the length of the concave or convex tube axis direction is L, −0.3 mm ≦ L By satisfying ≦ 1.5 mm, a peroxide layer 321 is formed on the surface of the inner lead 32, and at least a part of the peroxide layer 321 is positioned in the sealing portion 12. Even with an electrode mount, it is possible to realize a discharge lamp that has high tensile strength and is resistant to thermal shock, and has durability equal to or higher than that of a conventional electrode mount having beads.

  In the present embodiment, the beadless electrode mount 3 in which no beads are formed around the inner lead 32 is sealed at the lower end of the glass bulb 1 with the tube axis fixed substantially perpendicular to the ground. After performing the electrode mount arrangement process to be positioned on the planned attachment portion 13 and heating the planned sealing portion 32 to bring the glass bulb 1 into contact with the inner lead 32, the inner lead 32 is moved in the tube axis direction. The durability of the sealing portion 12 can be improved by performing a step of pushing the electrode mount 3 upward as an electrode mount moving step for moving the glass mount 1 relative to the center side.

  The inner lead 32 is made of a material having iron deposited on the surface such as kovar or iron-nickel alloy, and heats the surface of the inner lead 32 positioned outside the sealing portion 12 after the valve heating step. Then, after performing the peroxide layer forming step of forming the peroxide layer 321, the peroxide layer 321 can be positioned inside the sealing portion 12 by performing the electrode mount moving step.

(Second Embodiment)
FIG. 10 is a diagram for explaining a discharge lamp according to a second embodiment of the present invention.

  In the second embodiment, one end is sealed with beads and the other end is sealed with beads. In a lamp that seals and exhausts without using an exhaust tip, such as the present discharge lamp, the sealing process on one end side and the sealing process on the other end side are different. For example, the sealing process on the exhaust side (2nd side) has a difference such that the inside of the glass bulb 1 is performed at a pressure of 1 atm or less, or a mercury release medium is arranged at the end of the bulb. If included, beadless sealing is not suitable. Therefore, in order to facilitate manufacture, a beadless electrode mount may be used on the sealing side (1st side), and an electrode mount with beads may be used on the exhaust side (2nd side).

(Third embodiment)
FIG. 11 is a diagram for explaining a method of manufacturing a discharge lamp according to the third embodiment of the present invention.

  In the third embodiment, in the electrode mount moving step (d), the inner lead 32 is moved by pressing the glass bulb 1 downward by the pressing means 7 while the electrode mount 3 is fixed by the fixing member 8. It is made to move relative to the glass bulb 1 toward the center side in the tube axis direction. Even with this method, the same effects as those of the first embodiment can be obtained.

  The embodiment of the present invention is not limited to the above, and may be modified as follows, for example.

  The present invention is not limited to a cold cathode fluorescent lamp, and may be applied to a lamp such as a hot cathode fluorescent lamp.

  The peroxide layer 321 outside the sealing portion 12 may be removed. That is, there is no problem even if the excess peroxide layer 321 is removed while the peroxide layer 321 in the sealing portion 12 is left by performing the reduction treatment after the electrode mount 3 is sealed.

  In the electrode mount arrangement step of FIG. 3A, the line of the phosphor layer 2 may be used for the arrangement adjustment of the electrode mount 3. For example, by aligning the opening of the electrode 31 with the end of the phosphor layer 2, the variation in the overlap distance between the phosphor layer 2 and the electrode 31 after the electrode mount moving step (d) for each lamp. Can be reduced.

  The electrode mount moving process in FIG. 3D is performed at the same pushing distance D depending on the inner diameter and thickness of the glass bulb 1, the wire diameter of the inner lead 32, the heating amount, the heating time, and the like. Since the shape changes, it is desirable to adjust appropriately in consideration of them.

DESCRIPTION OF SYMBOLS 1 Glass bulb 11 Cylindrical part 12 Sealing part 13 Sealing scheduled part 2 Phosphor layer 3 Electrode mount 31 Electrode 32 Inner lead 321 Peroxide layer 33 Outer lead

Claims (6)

In a discharge lamp in which an electrode mount having an electrode and an inner lead is sealed at the end of the bulb,
The electrode mount is a beadless electrode mount in which beads are not formed around the inner lead,
The shape inside the bulb of the sealing portion where the electrode mount is sealed is a concave or convex shape, and when the length in the tube axis direction of the concave or convex shape is L, −0. A discharge lamp characterized by satisfying 3 mm ≦ L ≦ 1.5 mm (where the convex is positive).   The discharge lamp according to claim 1, wherein a peroxide layer is formed on a surface of the inner lead, and at least a part of the peroxide layer is located in the sealing portion.   The discharge lamp according to claim 1 or 2, wherein a beadless electrode mount is sealed at one end of the bulb, and an electrode mount with beads is sealed at the other end. In the method of manufacturing a discharge lamp in which an electrode mount having an electrode and an inner lead is sealed at the end of the bulb,
An electrode mount placement step in which the bead-less electrode mount in which beads are not formed around the inner lead is positioned at a sealing planned portion of the valve;
A valve heating step of heating the sealing portion and bringing the valve into contact with the inner lead;
An electrode mount moving step of moving the inner lead relative to the bulb toward the bulb central side in the tube axis direction.   5. The discharge lamp manufacturing method according to claim 4, wherein in the electrode mount moving step, the electrode mount is pushed upward while the bulb is maintained so that the tube axis is substantially perpendicular to the ground. Method.   The inner lead is made of a material in which iron is deposited on the surface, and after the valve heating step, the surface of the inner lead located outside the sealing portion is heated to form a peroxide layer. The discharge lamp manufacturing method according to claim 4 or 5, wherein after the layer forming step is performed, the electrode mount moving step is performed to position the peroxide layer in the sealing portion. Method.

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