JP2007157632A - Cold cathode discharge lamp, backlight unit, and manufacturing process for cold cathode discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold cathode discharge lamp provided with power supplying terminals on both ends of a glass bulb with cracking not easily occurring in the glass bulb, to provide a backlight unit with the cold cathode discharge lamp as a light source, and to provide a manufacturing method for the cold cathode discharging lamp. <P>SOLUTION: The cold cathode discharge lamp is provided with; an electrode 22 composed of an electrode main body 23 and a lead wire 24, the glass bulb 21 composed by sealing the lead wire 24 to an end part in a state with the electrode main body 23 stored inside, and a power supplying terminal 30 installed outside an end part of the glass bulb 21 and electrically connected to the lead wire 24. The power supplying terminal 30 is provided with; a cylindrical conductor 31 which have openings on both ends having the glass bulb 21 end part directly inserted from one end to the middle and a connecting conductor 32 electrically connecting the lead wire 24 and the cylindrical conductors 31 in the remaining space in the cylindrical conductor 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cold cathode discharge lamp in which a power supply terminal is disposed on the outer periphery of an end of a glass bulb, a backlight unit including the cold cathode discharge lamp as a light source, and a method for manufacturing the cold cathode discharge lamp.

  Conventionally, as shown in FIG. 9, there is a cold cathode discharge lamp 100 in which a power supply terminal 110 having a metal cap 112 fixed by solder 113 is provided at an end of a glass bulb 101 (Patent Document 1). The lead wire 104 of the electrode 102 is fixed to the end portion of the glass bulb 101 with the low melting point glass 105 in a state of being folded back along the end portion of the glass bulb 101. Since the power supply terminal 110 is electrically connected to the lead wire 104 of the electrode 102 via the solder 113, by fitting the power supply terminal 110 into a lamp holder (not shown) of a lighting device such as a backlight unit, The cold cathode discharge lamp 100 can be fixed to the lighting device, and the cold cathode discharge lamp 100 and the lighting circuit of the lighting device can be electrically connected. Therefore, when the cold cathode discharge lamp 100 is attached to the lighting device, it is not necessary to solder the lead wire 104 to the lighting circuit, and therefore, the lighting device can be compared with a cold cathode discharge lamp not provided with the power supply terminal 110. Is easy to install.

Further, the power supply terminal 110 plays a role of improving the heat dissipation of the cold cathode discharge lamp 100. That is, heat is transferred from the electrode body 103, which is at a high temperature when the lamp is lit, to the power supply terminal 110 through the lead wire 104, the glass bulb 101, etc., and is radiated from the power supply terminal 110 to the atmosphere. Increases nature.
JP-A-7-220622

  However, in Patent Document 1, since the metal cap 112 is attached to the lead wire 104 or the like folded back along the end of the glass bulb 101 via the solder 113, the solder that surrounds the outer periphery of the glass bulb 101. The thickness of 113 is increased. The lead wire 104 has a wire diameter of, for example, about 0.8 mm, the solder 113 has a sufficiently thick wall thickness, and the glass bulb 101 has a very thin wall, for example, about 0.5 mm. It is. Therefore, due to the heat generated during lamp lighting, the glass 113 is caused by the stress generated on the outer peripheral surface of the glass bulb 101 due to the difference in thermal expansion coefficient between the glass bulb 101 and the solder 113 interposed between the glass bulb 101 and the metal cap 112. There is a problem that a crack occurs in the valve 101.

  In view of the above problems, an object of the present invention is to provide a cold cathode discharge lamp that has a power supply terminal and is less likely to cause cracks in a glass bulb, a backlight unit including the same, and a method for manufacturing a cold cathode discharge lamp. .

  Therefore, a cold cathode discharge lamp according to the present invention includes an electrode composed of an electrode body and a lead wire, a glass bulb formed by sealing the lead wire at an end with the electrode body housed therein, A cold cathode discharge lamp provided with a power supply terminal that is disposed outside an end of a glass bulb and is electrically connected to the lead wire, the power supply terminal having openings at both ends, and from one end to the middle A cylindrical conductor into which the end portion of the glass bulb is directly inserted, and a connecting conductor for electrically connecting the lead wire and the cylindrical conductor in the remaining space of the cylindrical conductor. .

  In the above configuration, the glass bulb is directly inserted into the cylindrical conductor, and the lead wire and the cylindrical conductor are electrically connected in the remaining space of the cylindrical conductor. Since the connection conductor does not cover the side of the glass bulb as in Patent Document 1, when the lamp is lit and the glass bulb is stressed due to the difference in the thermal expansion coefficient between the connection conductor and the glass bulb. However, cracks are unlikely to occur in the glass bulb.

Here, it is preferable that the lead wire extends linearly along the tube axis direction of the glass bulb.
In the configuration of Patent Document 1, when the lead wire is folded back in the manufacturing process, a crack may occur at the end of the glass bulb. However, in the above configuration, the lead wire extends straight and needs to be folded back. Since there is no, there is no possibility that the glass bulb will crack in the manufacturing process. In addition, when the lead wire is bent as in the configuration of Patent Document 1, a narrow space is formed between the lead wire and the glass bulb end surface, but the glass bulb end surface is covered with solder to improve heat dissipation. Even if it is going to do, since it is hard for solder to enter into the said narrow space, it has a bad influence on the improvement of heat dissipation. In the above configuration, since the lead wire extends in a straight line, the narrow space as described above is not formed. Therefore, it is easy to coat the glass bulb end surface with solder, and thus heat dissipation can be easily improved. .

In addition, the glass bulb side surface of the connection conductor is formed in a shape that fits the glass bulb end surface, and the connection conductor is in close contact with the glass bulb end surface of the connection conductor. It is desirable to be provided in the state.
In the above configuration, the connection conductor and the end face of the glass bulb are in close contact, and the heat emitted from the electrode and transmitted to the glass bulb is efficiently transmitted to the cylindrical conductor via the connection conductor and radiated to the atmosphere. The heat dissipation of the cold cathode discharge lamp is improved. Moreover, the effect that lamp efficiency improves with the improvement in heat dissipation is also acquired.

Further, the connection conductor is preferably made of solder.
Since the solder is excellent in workability, the contact surface of the connecting conductor with the glass bulb end face can be easily formed into a shape suitable for the glass bulb end face. Moreover, since the solder is inexpensive, the cost of the cold cathode discharge lamp can be suppressed.
The connection conductor includes a first member made of solder and a second member made of a conductor other than solder and joined to the first member, and the first member is adapted to the end face of the glass bulb. It is good also as a structure which has the surface formed in the shape and is closely_contact | adhered to the said glass bulb end surface in the said surface.

In the above configuration, when the glass bulb and the connection conductor are joined in the manufacturing process, by heating the second member made of the conductor of the connection conductor, the first member made of solder that becomes a joint with the glass bulb, There is an advantage that heat for melting the solder of the first member is sufficiently transmitted.
In addition, the connection conductor includes a conductor plate made of a conductor other than solder and a solder body joined to the conductor plate, and the conductor plate has a surface formed in a shape suitable for the glass bulb end surface. It is good also as a structure which has and is closely_contact | adhered to the said glass bulb end surface in the said surface.

By disposing a conductor plate that is in close contact with the end face of the glass bulb, heat dissipation can be improved. In addition, since the cylindrical conductor and the conductor plate have high thermal conductivity and become hot due to the heat of the molten solder, there is an advantage that the molten solder easily flows into a narrow region formed by the cylindrical conductor and the conductor plate. .
Here, it is desirable that a plurality of through holes are formed in the conductor plate.

Thereby, since molten solder flows into the through-hole in the manufacturing process, the adhesion between the conductor plate and the glass bulb end surface is enhanced, and the heat transfer efficiency from the glass bulb to the conductor plate is enhanced.
A backlight unit according to the present invention is characterized in that any one of the cold cathode discharge lamps described above is provided in a light source. Thereby, since the cold cathode discharge lamp which is hard to produce a crack in a glass bulb is used as a light source, a long-life backlight unit can be provided.

  A manufacturing method of a cold cathode discharge lamp according to the present invention includes an electrode composed of an electrode body and a lead wire, a glass bulb formed by sealing the lead wire at an end with the electrode body housed therein, A cold cathode discharge lamp manufacturing method comprising a power supply terminal disposed outside an end of a glass bulb and electrically connected to the lead wire, the power supply terminal having openings at both ends, A cylindrical conductor into which the glass bulb end is inserted from the middle to the middle, and a connecting conductor for electrically connecting the lead wire and the cylindrical conductor in the remaining space of the cylindrical conductor, An insertion step of directly inserting the glass bulb end portion into the shape conductor, and a connection step of electrically connecting the lead wire and the cylindrical conductor with the connection conductor.

  In the cold cathode discharge lamp obtained by the above method, the glass bulb is directly inserted into the cylindrical conductor, and the lead wire and the cylindrical conductor are electrically connected in the remaining space of the cylindrical conductor. Even if it is in contact with the glass bulb end face, and the connection conductor does not cover the glass bulb side surface as in Patent Document 1, the glass due to the difference in thermal expansion coefficient between the connection conductor and the glass bulb during lamp lighting. Even when stress is generated in the bulb, an effect is obtained that the glass bulb is hardly cracked.

Further, the method includes a forming step of forming the surface of the connection conductor on the glass bulb side into a shape suitable for the glass bulb end surface before the connection step, and the connection step includes the connection conductor on the glass bulb side. It is desirable to include a close process for bringing a surface into close contact with the glass bulb end face.
Before the connection process, the glass bulb side surface of the connection conductor is formed into a shape that fits the glass bulb end surface, and the glass bulb side surface of the connection conductor is brought into close contact with the glass bulb end surface in the connection process. Since no gap is generated between the glass bulb and the connecting conductor, in the obtained cold cathode discharge lamp, heat transferred from the electrode to the glass bulb is transferred to the cylindrical conductor through the connecting conductor with high efficiency. Therefore, high heat dissipation is obtained.

Hereinafter, an external electrode type discharge lamp and a backlight unit according to an embodiment of the present invention will be described with reference to the drawings.
<Configuration of backlight unit>
First, the configuration of the backlight device according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic perspective view showing a configuration of a backlight unit 1 for a liquid crystal display having an aspect ratio of 16: 9 according to the present embodiment. In the figure, a part of the front panel 16 is cut away to show the internal structure.

As shown in FIG. 1, the backlight unit 1 includes a plurality of cold cathode discharge lamps (hereinafter referred to as “lamps”) 20, a housing 10 that has openings and accommodates these lamps 20, And a front panel 16 covering the opening of the housing 10.
The housing 10 is made of, for example, polyethylene terephthalate (PET) resin, and a reflective surface is formed by depositing a metal such as silver on the inner surface 11 thereof.

The lamps 20 have a straight tube shape, and in the present embodiment, 14 lamps 20 are arranged in the casing 10 in a direct manner. The configuration of the lamp 20 will be described later.
FIG. 2 is a diagram for explaining a mounting state of the lamp in the housing. As shown in FIG. 2, a set of lamp holders 12 is arranged on the inner surface 11 of the housing 10 at a position corresponding to the mounting position of each cold cathode discharge lamp 20. Each lamp holder 12 is formed by bending a copper alloy or aluminum plate material such as phosphor bronze, for example, and connects the pair of sandwiching pieces 12a and 12b to the sandwiching pieces 12a and 12b at the lower edge. It consists of a connecting piece 12c. The sandwiching pieces 12a and 12b are provided with recesses that match the outer shape of the cold cathode discharge lamp 20, and by inserting the cold cathode discharge lamp 20 into the recesses, the sandwiching pieces 12a and 12b are cooled by the leaf spring action of the sandwiching pieces 12a and 12b. The cathode discharge lamp 20 is held by the lamp holder 12 and the lamp holder 12 and the power supply terminal 30 are electrically connected. Electric power is supplied to the lamp 20 attached to the backlight unit 1 from the lighting circuit (not shown) of the backlight unit 1 via the lamp holder 12.

Further, an insulating plate 17 made of polycarbonate that insulates the lamp holder 12 and the housing 10 is disposed between the lamp holder 12 and the housing 10.
Returning to FIG. 1, the opening of the housing 10 is sealed with a translucent front panel 16 formed by laminating a diffusion plate 13 made of polycarbonate resin, a diffusion sheet 14 and a lens sheet 15 made of acrylic resin. .

The diffusion plate 13 and the diffusion sheet 14 in the front panel 16 scatter and diffuse the light emitted from the lamp 20, and the lens sheet 15 arranges the light in the normal direction of the sheet 15, Thus, the light emitted from the lamp 20 is configured to irradiate the front uniformly over the entire surface (light emitting surface) of the front panel 16.
In the above description, the backlight unit is of the direct type, but it may be of a so-called edge light type.

<Lamp configuration>
FIG. 3 is a partially broken perspective view showing a cold cathode discharge lamp according to an embodiment of the present invention, and FIG. 4 is an enlarged sectional view showing one end portion of the cold cathode discharge lamp. The lamp 20 is used as a light source of the backlight unit 1, and includes a glass bulb 21, a pair of hollow electrodes 22 sealed at both ends of the glass bulb 21, and outside the both ends of the glass bulb 21. And a power supply terminal 30 provided.

The glass bulb 21 is obtained by processing a glass tube made of borosilicate glass (SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —K ₂ O—TiO ₂ ) and has a total length of 730 mm.
The glass bulb 21 has an annular cross section, an outer diameter of 4 mm, an inner diameter of 3 mm, and a wall thickness of 0.5 mm. The maximum width of the sealing portion in the tube axis direction of the glass bulb 21 is 2 mm, and the hollow electrode 22 is sealed.

The configuration of the glass bulb 21 is not limited to the above configuration. However, in order to make the cold cathode discharge lamp 20 elongated, it is desirable that the glass bulb 21 has a small diameter and a thin wall. Therefore, in general, the outer diameter of the glass bulb 21 is 1.8 mm (inner diameter 1.4 mm) to It is preferably 6.0 mm (inner diameter: 5.0 mm).
A phosphor layer 29 is formed on the inner surface of the glass bulb 21. The phosphor layer 29 is made of, for example, a red rare earth (Y ₂ O ₃ : Eu), a green phosphor (LaPO ₄ : Ce, Tb), and a blue phosphor (BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn). It is made of a phosphor. The glass bulb 21 is filled with, for example, about 1200 μg of mercury and about 8 kPa (20 ° C.) neon / argon mixed gas (Ne 95% + Ar 5%) as a rare gas.

The configuration of the phosphor layer 29, mercury, and rare gas is not limited to the above configuration. For example, a neon / krypton mixed gas (Ne 95% + Kr 5%) may be enclosed as a rare gas. When a neon / krypton mixed gas is used as the rare gas, lamp startability is improved, and the cold cathode discharge lamp 20 can be lit at a low voltage.
The hollow electrode 22 includes an electrode body 23 and a lead wire 24 and is sealed to a sealing portion of the glass bulb 21.

The electrode body 23 is made of nickel (Ni) and has a bottomed cylindrical shape. In addition, the electrode main body 23 is not limited to nickel, For example, it is possible to make it from niobium (Nb), a tantalum (Ta), or molybdenum (Mo).
The electrode body 23 has a total length of 5.2 mm, an outer diameter of 2.7 mm, an inner diameter of 2.3 mm, and a wall thickness of 0.2 mm. The hollow electrode 22 is disposed so that the tube axis of the electrode main body 23 and the tube axis of the glass bulb 21 are substantially coincident with each other, and the distance between the outer peripheral surface of the electrode main body 23 and the inner surface of the glass bulb 21 is set as follows. Is substantially uniform over the entire outer periphery of the.

  The distance between the outer peripheral surface of the electrode body 23 and the inner surface of the glass bulb 21 is specifically 0.15 mm. When the interval is narrow in this way, discharge does not enter the interval and discharge occurs only inside the hollow electrode 22. Therefore, the sputtered material scattered by the discharge is less likely to adhere to the inner surface of the glass bulb 21, and the cold cathode discharge lamp 20 has a long life. On the other hand, since the discharge does not go to the lead wire 24 side, the lead wire 24 is hardly heated by the discharge.

In addition, although the space | interval of the outer peripheral surface of the electrode main body 23 and the inner surface of the glass bulb 21 does not necessarily need to be 0.15 mm, it may be 0.2 mm or less in order to prevent discharge from entering the space. preferable.
The lead wire 24 extends linearly along the tube axis direction of the glass bulb. In the configuration of Patent Document 1, when the lead wire is bent in the manufacturing process, a crack may occur in the end portion of the glass bulb. By making the lead wire 24 straight, the glass bulb 21 is cracked in the manufacturing process. There is no risk of occurrence. In addition, when the lead wire is bent as in the configuration of Patent Document 1, a narrow space is formed between the lead wire and the glass bulb end surface, but the glass bulb end surface is covered with solder to improve heat dissipation. Even if it is going to be, it is difficult to improve heat dissipation because it is difficult for solder to enter the narrow space, but in the configuration according to the present embodiment, the lead wire 24 extends in a straight line. Since such a narrow space is not formed, the end face of the glass bulb can be easily covered with solder, so that heat dissipation can be improved.

  The lead wire 24 is a connection between an internal lead wire 25 made of tungsten (W) and an external lead wire 26 made of nickel that easily adheres to solder or the like, and a joint surface between the internal lead wire 25 and the external lead wire 26. However, it is substantially flush with the outer surface of the glass bulb 21. That is, the internal lead wire 25 is located inside the outer surface of the glass bulb 21, and the external lead wire 26 is located outside the outer surface of the glass bulb 21.

The internal lead wire 25 has a substantially circular cross section, a total length of 3 mm, and a wire diameter of 0.8 mm. The internal lead wire 25 has an end on the external lead wire 26 side sealed to the sealing portion of the glass bulb 21, and an end opposite to the external lead wire 26 side is substantially the outer surface of the bottom of the electrode body 23. It is joined at the center.
The external lead wire 26 is joined to the power supply terminal 30 at a protruding portion that protrudes from the outer surface of the glass bulb 21 toward the tube axis direction. The external lead wire 26 has a total length of 1 to 10 mm, for example, 2 mm, and the axis of the external lead wire 26 and the tube axis of the glass bulb 21 substantially coincide. If the total length of the external lead wire exceeds 10 mm, a crack may occur at the glass bulb end due to the stress of the external lead wire, and at least 1 mm or more is necessary to fulfill the function of the external lead wire. The external lead wire 26 has a substantially circular cross section, and the wire diameter is 0.6 mm, which is narrower than the internal lead wire 25.

  The power supply terminal 30 is provided so as to cover the end of the glass bulb 21. The power supply terminal 30 includes a cylindrical conductor 31 made of, for example, an iron-nickel alloy and having openings at both ends, and a connection conductor 32 made of solder and inserted into the cylindrical conductor 31. In addition, the solder which comprises the connection conductor 32 consists of a composition of Sn: 96.5%, Ag: 3.0%, Cu: 0.5%, for example. The composition of the solder is not limited to the above, and may include, for example, at least one kind of bismuth, antimony, zinc, lead and the like. However, in order to obtain an environmentally friendly lamp, it is preferable that no environmentally hazardous substances such as lead and antimony are included.

The cylindrical conductor 31 has an inner diameter of 4 mm substantially equal to the outer diameter of the glass bulb 21, the outer diameter is 4.1 mm, and the thickness is 0.05 mm.
5A and 5B are diagrams illustrating the connection conductor, in which FIG. 5A is a perspective view of the connection conductor, and FIG. 5B is a cross-sectional view of the connection conductor.
As shown in FIGS. 5A and 5B, the connection conductor 32 has a substantially cylindrical shape in appearance, and its outer diameter is equal to the inner diameter of the cylindrical conductor 31 and is 4 mm. One end face (left end face in the figure) 32a of the connection conductor 32 has a shape that fits the end face 21a of the glass bulb 21, and the other end face (right end face in the figure) 32b is a flat surface. Further, the connection conductor 32 is formed with a hollow hole 32c into which the external lead wire 26 is inserted into the column axis. The diameter of the hollow hole 32 c is 0.6 mm which is substantially equal to the wire diameter of the external lead wire 26.

Returning to FIG. 4, the glass bulb 21 is inserted from one end to the middle of the cylindrical conductor 31 of the power supply terminal 30, and the connection conductor 32 is inserted in the remaining space of the cylindrical conductor 31. At this time, the external lead wire 26 is inserted into the hollow hole 32 c of the connection conductor 32. Thereby, the electrode 22 and the cylindrical conductor 31 are electrically connected.
In the above configuration, since the glass bulb 21 is directly inserted into the cylindrical conductor 31 and the external lead wire 26 and the cylindrical conductor 31 are electrically connected in the remaining space of the cylindrical conductor 31, the connecting conductor 32 is the glass bulb. Even if it contacts the glass bulb end surface 21a, and since the connection conductor does not cover the glass bulb side surface as in Patent Document 1, the coefficient of thermal expansion between the connection conductor 32 and the glass bulb 21 during lamp lighting. Even when a stress is generated in the glass bulb 21 due to the difference, there is an advantage that the glass bulb 21 is hardly cracked.

Further, as the length L from the end face of the power supply terminal 30 to the glass bulb end face 21a shown in FIG. 4 is longer, the surface area of the power supply terminal 30 is increased and heat dissipation is improved. Specifically, the length L is preferably longer than the outer diameter R of the glass bulb 21.
<Method for Manufacturing Cold Cathode Discharge Lamp>
Next, a manufacturing method of the cold cathode discharge lamp according to the present embodiment will be described. The method for manufacturing the lamp 20 according to the present embodiment is characterized by the method for forming the power supply terminal 30. Since the formation method of the phosphor layer 29, the glass bulb 21 and the like is in accordance with a known technique, description thereof will be omitted, and the formation method of the feeding terminal 30 will be described in detail below.

According to a known method in advance, a phosphor layer 29 is formed on the inner wall, and a glass bulb 21 in which a pair of electrodes 22 are sealed with mercury and buffer rare gas sealed therein is formed.
First, a cylindrical conductor 31 and a connection conductor 32 are prepared as components of the power supply terminal 30. The cylindrical conductor 31 can be obtained by forming an iron-nickel alloy into a cylindrical shape having an inner diameter substantially equal to the outer diameter of the glass bulb 21.

And the edge part of the glass bulb | bulb 21 is directly inserted in the area | region about 50% of the total length of the axial direction of the cylindrical conductor 31 (insertion process).
In the previous researches of the present inventors, in order to improve the heat dissipation of the lamp, an attempt was made to pour and fill the space formed by the cylindrical conductor 31 and the glass bulb end surface 21, but the solder is a glass bulb. It was found that a narrow gap formed between the curved portion of the end face 21a and the cylindrical conductor 31 does not enter, and a gap is generated, which hinders heat dissipation of the lamp. The above-mentioned gap is generated by the present inventors when the solder is filled, because the glass bulb does not reach a high temperature when the solder is filled. It has been clarified that this is caused by the fact that solder does not easily enter the gap. Based on this result, the present inventors formed a solder body having a shape surface suitable for the glass bulb end surface 21a, instead of pouring molten solder, and filled the narrow gap with the solder body. The idea of melting and soldering the solder body was conceived.

  Based on the above viewpoint, the connection conductor 32 is formed as follows. First, a columnar solder body is formed. At this time, the outer diameter of the cylindrical solder body is made substantially equal to the inner diameter of the cylindrical conductor 31. Then, a cylindrical hollow hole 32 c having a diameter substantially equal to the wire diameter of the external lead wire 26 is formed on the column axis of the cylindrical solder body. Furthermore, one end surface of the columnar solder body is processed into a shape compatible with the glass bulb end surface 21a (forming step). Thereby, the connection conductor 32 as shown in FIG. 5 is obtained.

It continues and the attachment process of the electric power feeding terminal 30 is demonstrated. After the end of the glass bulb 21 is directly inserted from one end to the middle of the cylindrical conductor 31, the connecting conductor 32 is connected to the cylindrical conductor 31 while inserting the external lead wire 26 of the electrode 22 into the hollow hole 32 c of the connecting conductor 32. Interpolate to At this time, the surface 32a of the connection conductor 32 and the glass bulb end surface 21a are brought into close contact with each other.
Heat is applied to the cylindrical conductor 31 to melt the connecting conductor 32 made of solder, and is brought into close contact with the cylindrical conductor 31 and the end face of the glass bulb. Since the surface 32a on the glass bulb 21 side of the connecting conductor 32 has a shape that fits the glass bulb end surface 21a, solder is also applied to a narrow gap formed between the curved portion of the glass bulb end surface 21a and the cylindrical conductor 31. Enters, and the surface 32a of the connection conductor 32 is in close contact with the end face of the glass bulb (contact process).

By the above-described method, no gap is generated between the glass bulb end surface 21a and the connection conductor 32, and the glass bulb 21 and the connection conductor 32 are in close contact with each other. Further, the connection conductor 32 electrically connects the external lead wire 26 and the cylindrical conductor 31 (connection process).
In the cold cathode discharge lamp 20 obtained by the above manufacturing method, the glass bulb 21 is directly inserted into the cylindrical conductor 31, and the external lead wire 26 and the cylindrical conductor 31 are electrically connected in the remaining space of the cylindrical conductor 31. Therefore, even if the connection conductor 32 comes into contact with the glass bulb 21, it is on the glass bulb end face 21a, and the connection conductor does not cover the side surface of the glass bulb as in Patent Document 1. Even when a stress is generated in the glass bulb 21 due to the difference in thermal expansion coefficient between the glass bulb 21 and the glass bulb 21, the glass bulb 21 is hardly cracked. Further, since the lead wire is straight and it is not necessary to bend the lead wire, there is no possibility that the glass bulb will crack in the manufacturing process. Further, since the connection conductor 32 is provided in close contact with the end face of the glass bulb, the heat generated from the electrode body 23 is transmitted to the power supply terminal 30 with high efficiency via the glass bulb 21, the lead wire 24 and the like. Therefore, the heat is dissipated into the atmosphere, so that it has high heat dissipation.

<Modification>
As described above, the present invention has been described based on the embodiments. However, the content of the present invention is not limited to the specific examples shown in the above-described embodiments. For example, the following modifications are possible. Can think.
(Modification 1)
In the above, the connection conductor of the power supply terminal 30 has been described as having a structure as shown in FIG. 5, but the connection conductor is not limited to this, and may have other forms as follows.

FIG. 6 is a cross-sectional view showing the configuration of another connection conductor, and FIG. 6A is a view showing a first modification of the connection conductor.
As shown in FIG. 6A, the connection conductor 33 according to the first modified example includes a main body portion 35 and a solder body 34. The main body 35 is made of, for example, copper and has a hollow cylindrical shape having a hollow hole into which the external lead wire 26 is inserted. A solder body 34 is joined to one end surface (the left end surface in the figure) of the main body 35. The solder body 34 has a substantially hollow disk shape in appearance, and the surface 34 a opposite to the joint surface with the main body portion 35 is processed into a shape suitable for the end surface 21 a of the glass bulb 21. In the configuration shown in FIG. 6A, when the glass bulb 21 and the connection conductor 33 are joined in the manufacturing process, the main body portion 35 is heated, so that the solder body 34 serving as a joint portion with the glass bulb is soldered. There is an advantage that the heat for melting is sufficiently transferred.

The case where the power supply terminal is formed on the glass bulb 21 using the connection conductor 33 will be briefly described.
The connecting conductor 33 is inserted into the cylindrical conductor, and the surface 34 a of the connecting conductor 33 is brought into contact with the end face of the glass bulb 21. At this time, since the surface 34a of the solder body 34 has a shape that fits the end surface of the glass bulb 21, the solder body 34, that is, the connection conductor 33 and the end surface 21a of the glass bulb 21 are in close contact with each other. In this state, heat is applied from the end face of the main body 35 until the solder body 34 reaches a melting temperature. When the solder body 34 is melted, the heat application is stopped and natural cooling is performed. When the power supply terminal is attached by the above method, the solder enters the narrow space formed by the glass bulb end surface 21a and the cylindrical conductor 31, so that the connection conductor 33 is joined without any gap between the glass bulb and the connection. The conductor 33 and the glass bulb end surface 21a, as a result, the feeding terminal 30 and the glass bulb 21 are in close contact with each other.

  FIG. 6B is a diagram showing a second modification of the connection conductor. As shown in FIG. 6B, the connection conductor 36 according to the second modification example includes a main body portion 38 and a solder film 37. The main body portion 38 is made of, for example, copper and has a substantially hollow cylindrical shape in appearance, and one end surface (left side in the drawing) 38a of the main body portion 38 is processed into a shape suitable for the glass bulb end surface 21a. A solder film 37 is applied to the end surface 38 a of the main body 38. Since the solder film 37 is applied to the end face 38a of the main body 38 with a uniform thickness, the surface 37a of the solder film 37 has a shape that fits the glass bulb end face 21a. In the configuration shown in FIG. 6B, as in the configuration shown in FIG. 6A, when the glass bulb 21 and the connection conductor 36 are joined in the manufacturing process, the main body 38 is heated, whereby the glass bulb is heated. There is an advantage that heat for melting the solder is sufficiently transmitted to the solder film 37 to be a joint portion with the solder. Further, since the surface 37a of the solder film 37 is shaped to fit the glass bulb end surface 21a simply by applying the solder film 37 to the end surface 38a of the main body 38 with a uniform thickness, the manufacturing process can be simplified. .

  The method of forming the power supply terminal on the glass bulb using the connection conductor 36 is the same as the case of using the connection conductor 33 described above. The connection conductor 36 and the glass bulb end surface 21a are in close contact with each other. In this state, heat is applied from the end face of the main body portion 38 until the solder body 33 reaches a melting temperature. When the solder film 37 is melted, the application of heat is stopped and natural cooling is performed. As a result, solder also enters a narrow space formed by the glass bulb end surface 21a and the cylindrical conductor 31, so that the connecting conductor 36 is joined without any gap between the glass bulb 21 and the power supply terminal and the glass bulb 21 are joined. And will be in close contact.

  FIG. 6C is a diagram illustrating a third modification of the connection conductor. As shown in FIG. 6C, the connection conductor 46 according to the third modified example includes a main body 48 and a solder film 47. The main body 48 is made of, for example, copper and has a hollow cylindrical shape having a hollow hole into which the external lead wire 26 is inserted. One end surface (the end surface on the left side in the figure) and the side surface of the main body 48 are covered with a solder film 47. Of the solder film 47, the surface 48 a that contacts the end surface of the glass bulb is processed into a shape that fits the end surface 21 a of the glass bulb 21.

  The case where the power supply terminal is formed on the glass bulb 21 using the connection conductor 46 will be briefly described. The connecting conductor 46 is inserted into the cylindrical conductor, and the surface 46 a of the connecting conductor 46 is brought into contact with the end face of the glass bulb 21. At this time, the surface 34a of the solder body 34 has a shape that matches the end surface of the glass bulb 21, so that the solder body 34, that is, the connection conductor 46 and the end surface 21a of the glass bulb 21 are in close contact with each other. In this state, heat is applied from the end face of the main body 48 until the solder film 47 reaches a melting temperature. When the solder film 47 is melted, the application of heat is stopped and natural cooling is performed. When the power supply terminal is attached by the above method, the solder enters the narrow space formed by the glass bulb end surface 21a and the cylindrical conductor 31, so that the connection conductor 46 is joined and connected without any gap between the glass bulb. The conductor 46 and the glass bulb end surface 21a, as a result, the power supply terminal 30 and the glass bulb 21 are in close contact with each other. In addition, since the solder film 47 is melted and solidified, the side surface of the solder film 47 and the cylindrical conductor 31 are brought into close contact with each other and are electrically and thermally connected.

(Modification 2)
In the above description, the power supply terminal has been described with respect to the configuration including the cylindrical conductor 31 and the connection conductor 32 as illustrated in FIG. 4, but the configuration of the power supply terminal may be other configurations.
FIG. 7 is an enlarged cross-sectional view showing one end portion of a cold cathode discharge lamp according to a modification, and is a diagram for explaining a modification of the power supply terminal.

As shown in FIG. 7A, the power supply terminal 40 according to the modification includes a cylindrical conductor 41, a conductor plate 42, and a solder body 43.
The conductor plate 42 is made of, for example, an iron-nickel alloy that is the same material as the cylindrical conductor 41. The conductor plate 42 has an outer diameter that is substantially equal to the inner diameter of the cylindrical conductor 41, and a contact surface with the glass bulb 21 that fits the end face 21 a of the glass bulb 21.

  Here, the process of attaching the power supply terminal 40 to the glass bulb 21 will be described. First, the glass bulb 21 is inserted into the cylindrical conductor 41 by a predetermined length. Next, the external lead wire 26 is inserted into the hollow hole of the conductor plate 42, the conductor plate 42 is inserted into the cylindrical conductor 41, and is brought into close contact with the end face of the glass bulb 21. Then, the glass bulb 21 is arranged so that the tube axis faces in the vertical direction, and molten solder is poured into a space defined by the inner wall of the cylindrical conductor 41 and the conductor plate 42. Since the cylindrical conductor 41 and the conductor plate 42 have high thermal conductivity and become high temperature due to the heat of the molten solder, the molten solder flows into a narrow region formed by the cylindrical conductor 41 and the conductor plate 42.

Since the conductor plate 42 and the glass bulb 21 are in close contact with each other, the heat transfer efficiency from the glass bulb 21 to the conductor plate 42 is increased. Thereby, the heat generated from the electrode body 23 is radiated with high efficiency from the cylindrical conductor 41 connected to the conductor plate 42 to the atmosphere, so that the heat dissipation of the cold cathode discharge lamp 20 is enhanced.
Here, a plurality of through holes may be formed in the conductor plate 42. Thereby, since molten solder flows into the through-hole in the forming step, the adhesion between the conductor plate 42 and the end face of the glass bulb 21 is enhanced, and the heat transfer efficiency from the glass bulb 21 to the conductor plate 42 is enhanced. Note that it is preferable to form a plurality of through holes with a diameter of 3 mm or less, for example, about 0.5 mm.

Further, the cylindrical conductor 41 and the conductor plate 42 in FIG. 7A are welded in advance, and the cylindrical conductor and the conductor plate are integrated as shown in FIG. 7B. A cylindrical conductor 44 may be used.
(Other variations)
FIG. 8 is a perspective view showing a modification of the cylindrical conductor. The cylindrical conductor 50 according to the modification is substantially cylindrical in appearance, and has a slit 51 formed in the cylinder axis direction, and the shape of the cut surface perpendicular to the cylinder axis is C-shaped. Using this cylindrical conductor 51, when a feeding terminal is arranged at the end of the glass bulb and the cylindrical conductor and the external lead wire are connected by a connecting conductor made of, for example, solder, the gap between the glass bulb and the solder It is considered that the effect that the air gap is hardly generated between the glass bulb and the connecting conductor can be obtained because the air bubbles in the air gap that can be generated in the above are released from the slit 51.

  The present invention can be widely applied to cold cathode discharge lamps and backlight units. Moreover, since the present invention can provide a cold cathode discharge lamp with high accuracy of mounting to the lamp holder, its industrial utility value is extremely high.

It is a schematic perspective view which shows the structure of the backlight unit for liquid crystal displays of the aspect ratio 16: 9 which concerns on this Embodiment. It is a figure for demonstrating the attachment state of the lamp | ramp in a housing | casing. 1 is a partially broken perspective view showing a cold cathode discharge lamp according to an embodiment of the present invention. It is an expanded sectional view which shows the one end part of a cold cathode discharge lamp. FIG. 5A is a perspective view of the connection conductor, and FIG. 5B is a cross-sectional view of the connection conductor. FIG. 6A is a cross-sectional view showing a configuration of another connection conductor, FIG. 6A is a diagram showing a first modification of the connection conductor, and FIG. 6B is a diagram showing a second modification of the connection conductor; FIG. 6C is a diagram showing a third modification of the connection conductor. It is an expanded sectional view which shows the one end part of the cold cathode discharge lamp which concerns on a modification, Comprising: It is a figure for demonstrating the modification of a feed terminal. It is a perspective view which shows the modification of a cylindrical conductor. It is sectional drawing which shows the structure of the conventional cold cathode discharge lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Backlight unit for liquid crystal display 10 Case 12 Lamp holder 20 Cold cathode discharge lamp 21 Glass bulb 21a Glass bulb end surface 22 Electrode 23 Electrode main body 24 Lead wire 26 External lead wire 29 Phosphor layer 30 Feed terminal 31 Cylindrical conductor 32 Connection Conductor 42 Conductor plate

Claims (10)

An electrode composed of an electrode body and a lead wire; a glass bulb formed by sealing the lead wire at an end in a state where the electrode body is housed inside; and an outer end portion of the glass bulb, A cold cathode discharge lamp comprising a power supply terminal electrically connected to a lead wire,
The power supply terminal is
A cylindrical conductor having openings at both ends and directly inserting the glass bulb end from one end to the middle;
A cold cathode discharge lamp comprising: a connecting conductor for electrically connecting the lead wire and the cylindrical conductor in a remaining space of the cylindrical conductor.   The cold cathode discharge lamp according to claim 1, wherein the lead wire extends linearly along the tube axis direction of the glass bulb. The glass bulb side surface of the connection conductor is formed in a shape that fits the glass bulb end surface,
The cold cathode discharge lamp according to claim 1 or 2, wherein the connection conductor is provided in a state in which a surface of the connection conductor on the glass bulb side is in close contact with the end face of the glass bulb. The cold cathode discharge lamp according to any one of claims 1 to 3, wherein the connection conductor is made of solder. The connection conductor comprises a first member made of solder and a second member made of a conductor other than solder and joined to the first member,
The cold cathode discharge according to claim 3, wherein the first member has a surface formed in a shape that fits the glass bulb end surface, and is in close contact with the glass bulb end surface. lamp. The connection conductor is composed of a conductor plate made of a conductor other than solder and a solder body joined to the conductor plate.
The cold-cathode discharge lamp according to claim 3, wherein the conductor plate has a surface formed in a shape that matches the end face of the glass bulb, and is in close contact with the end face of the glass bulb. . The cold cathode discharge lamp according to claim 6, wherein a plurality of through holes are formed in the conductor plate.   A backlight unit comprising the cold cathode discharge lamp according to any one of claims 1 to 7 as a light source. An electrode composed of an electrode body and a lead wire; a glass bulb formed by sealing the lead wire at an end in a state in which the electrode body is housed therein; and an outside of the end of the glass bulb, the lead A cold cathode discharge lamp manufacturing method comprising a power supply terminal electrically connected to a wire,
The power supply terminal has openings at both ends, a cylindrical conductor into which the glass bulb end is inserted from one end to the middle, and the lead wire and the cylindrical conductor in the remaining space of the cylindrical conductor. A connecting conductor for electrical connection;
An insertion step of directly inserting the glass bulb end into the cylindrical conductor;
A method of manufacturing a cold cathode discharge lamp, comprising: a connection step of electrically connecting the lead wire and the cylindrical conductor with the connection conductor. Including a molding step of molding the surface on the glass bulb side of the connection conductor into a shape suitable for the glass bulb end surface, before the connection step;
The method for manufacturing a cold cathode discharge lamp according to claim 9, wherein the connecting step includes a close step of bringing a surface of the connection conductor on the glass bulb side into close contact with the glass bulb end surface.

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