JP2002229466A - Light source device and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device capable of stabilizing characteristics of a light source lamp. SOLUTION: In this light source device, the end part 4a of a heater which is positioned along the outer surface of a light source lamp and the end part of a twisted wire 5a which is coated with an electric insulating coating layer 5b are connected with a conductive metal fitting 6. The metal fitting 6 is provided with a base plate part 15 having a flat face 15b, and an electric wire connection part 17 having a pair of electric wire calking pieces 19, which are provided so as to be bent from the both side edges of the base plate part to direct the flat face 15b in a state in which top end parts each other 19a are made to meet together and a heater connection part 15a. The end part 4a of the heater is fixed by welding to the heater connection part 15a. Moreover, an electric wire 5 is fixed by calking to the electric wire connection part 17 by making end part of the twisted wire 5a to be glued respectively to the flat face 15b of the base plate part 15, the base side parts 19b of the both calking pieces 19, top end parts 19 of the both calking pieces 19 by the pair of the calking pieces 19. As a result the total resistance value of a current path to the heater is made small and characteristics of the light source lamp is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device such as a meter and a car navigator mounted on a vehicle, and a light source device used as a backlight of the display device.
The present invention also relates to a light source device used for reading a document of an OA device such as an OCR.

[0002]

2. Description of the Related Art A light source device of a car navigator for displaying a liquid crystal has a light source lamp composed of a cold cathode fluorescent lamp. It is known that this lamp has poor lighting startability in a low temperature environment such as below freezing, from the start of lighting until reaching a stable lighting state in which a predetermined brightness is obtained. Therefore, generally, a heater is provided along the outer peripheral surface of the light source lamp, and the above-described startability is improved by a heating action accompanying the heat generated by the heater.

[0003] An electric wire is connected to a terminal portion of the heater for energizing the heater. Generally, a single wire of an Fe-Ni alloy is used for the heater, and a wire formed by covering a stranded wire with an electrically insulating coating layer is used for the electric wire. The use of an electric wire having a stranded wire is excellent in that there is very little possibility of disconnection when the electric wire is routed.

[0004] The heater and the electric wire are overlapped with the terminal of the stranded wire protruding from the coating layer and the terminal of the heater from opposite directions, and a metal caulking band is wound around the joined portion. By caulking this band, they are mechanically and electrically connected to each other.

[0005] As described above, both the terminal portion of the heater and the terminal portion of the stranded wire which are directly caulked are exposed to the atmosphere, and it is inevitable that their surfaces are oxidized. In particular, since the heater is made of an Fe-Ni alloy, it is easily oxidized.

Therefore, even if the mechanical connection by the crimping is maintained, the contact resistance of the crimping portion at the crimping portion changes as the oxidation of the surface of the heater terminal portion and the like progresses. Therefore, the current path including the current path changes so as to increase the total resistance value, so that the characteristics of the light source lamp may be adversely affected. Accordingly, the display performance of a liquid crystal display device using the light source device as a backlight may be adversely affected.

In a light source device for reading an original of an OA device such as an OCR, an external electrode is provided along the outer surface of the light source lamp, and the terminal portion of the electrode is covered with an electrically insulating coating layer. There is known one in which terminal portions of a stranded wire are connected using a caulking band as described above. And
Even in such a light source device, the surface resistance of the external electrode terminal portion changes so that the total resistance value of the current path including the caulked portion increases, so that a situation that adversely affects the characteristics of the light source lamp is likely to occur. .

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device capable of stabilizing the characteristics of a light source lamp and a liquid crystal display device having a stable display performance.

[0009]

According to the first aspect of the present invention,
A light source lamp composed of a low-pressure mercury vapor discharge lamp, a heater provided along the outer surface of the light source lamp, a stranded wire electrically connected to a terminal portion of the heater, and an electric insulation covering the stranded wire. It is assumed that the light source device includes an electric wire having a coating layer.

[0010] In order to solve the above-mentioned problem, the invention according to claim 1 connects a heater and terminal portions of a stranded wire via a conductive joint fitting, and the joint fitting is connected to a terminal of the heater. A substrate portion having a heater connection portion connected by welding, and a flat portion of the substrate portion which is bent from both side edges of the substrate portion at positions deviated from the heater connection portion so that tips of the substrate portions are opposed to each other. It has a pair of electric wire caulking pieces provided so as to face one surface, and the end portion of the stranded wire protruding from the coating layer is at least one flat surface of the substrate portion, the root of both electric wire caulking pieces. It is characterized in that it has a side portion and an electric wire connection portion which is caulked in close contact with a tip portion of each of the electric wire caulking pieces.

In the invention according to claim 1, a cold cathode fluorescent lamp or the like can be preferably used as a light source lamp as a low-pressure mercury vapor discharge lamp, and its shape is linear, L-shaped, or as shown in the embodiment. It can be arbitrarily determined such as a meandering meandering shape. In the invention according to claim 1, the heater includes Fe-
In addition to the use of Al engaging gold or a Ni-Cu alloy, the heater can be formed in a linear shape and wound around the outer periphery of the light source lamp. Can also be provided so as to extend in the axial direction of. Further, in the invention according to claim 1, the joint fitting can be preferably made of a metal material such as Ni, phosphor bronze, or brass that is somewhat hard and can maintain shape retention after bending, and this fitting is preferably used. Whether or not there is a portion for caulking the coating layer of the electric wire can be arbitrarily selected. Further, welding of the terminal portion of the heater to the heater connection portion of the fitting can be performed by resistance welding, laser welding, arc welding, or the like. Particularly, the implementation by resistance welding is inexpensive and requires low equipment costs. This is preferable in that welding can be stopped.

In the invention according to the first aspect, the terminal of the electric wire and the terminal of the heater for heating the light source lamp are connected via a conductive fitting. Since the metal structure of the heater connection portion of the joint fitting and the terminal portion of the heater, which are welded together, are melted and joined to each other, the influence of the oxidation of the heater does not reach the fusion joint portion. The contact resistance at this joint can be reduced and stabilized. In addition, the wire connection part of the joint fitting and the stranded wire end of the wire are crimped by plastically deforming a pair of wire caulking pieces of the wire connection part. Since it is fixed at least to the flat surface of the substrate portion, the root side portions of the two electric wire caulking pieces, and the tip portions of the two electric wire caulking pieces, the contact resistance at the caulked portion can be reduced, and compared with the heater. As a result, the stranded wire is not easily oxidized, and therefore, the contact resistance at the caulked portion can be reduced and can be stabilized.

According to a second aspect of the present invention, there is provided a light source lamp comprising a discharge lamp, an external electrode provided along an outer surface of the light source lamp, a stranded wire electrically connected to a terminal portion of the electrode, and a stranded wire. And a wire having a coating layer made of an electrically insulating material covered with a stranded wire.

In order to solve the above-mentioned problem, the invention according to claim 2 connects the external electrode and the ends of the stranded wire via a conductive joint fitting, and the joint fitting is connected to the external electrode. The terminal portion of the substrate portion has an electrode connection portion connected by welding, and the substrate portion is bent from both side edges of the substrate portion at a position deviated from the electrode connection portion, and the front ends of the substrate portions are opposed to each other. A pair of electric wire caulking pieces provided so as to face one flat surface of the stranded wire, and the terminal portion of the stranded wire protruding from the coating layer is at least one flat surface of the substrate portion, and the two electric wire caulking pieces. And a wire connection portion which is caulked closely to the tip of each of the electric wire caulking pieces.

In the invention according to claim 2, as the light source lamp, for example, a cold cathode fluorescent lamp or a rare gas discharge lamp containing no metal vapor such as mercury can be suitably used as a discharge lamp. Shape, L-shape, or the like. In the invention according to claim 2, the external electrode includes:
This external electrode can be formed in a linear shape and wound around the outer periphery of the light source lamp. Alternatively, the external electrode can be formed in a plate shape. The light source lamp may be provided so as to be extended in the axial direction of the light source lamp. Further, in the invention according to claim 2, the joint fitting can be preferably made of a metal material such as Ni, phosphor bronze, or brass that is somewhat hard and can maintain shape retention after bending, and this fitting is preferably used. Whether or not there is a portion for caulking the coating layer of the electric wire can be arbitrarily selected. Furthermore, welding of the terminal portion of the external electrode to the electrode connection portion of the fitting is
Resistance welding, laser welding, or arc welding can be performed, but especially in resistance welding, the equipment cost is low,
This is preferable because welding can be performed at low cost.

In the invention according to claim 2, the terminal of the electric wire and the terminal of the external electrode attached to the light source lamp are connected via a conductive joint fitting. Since the metal connection of the electrode connection portion of the joint fitting and the terminal portion of the external electrode that are welded are fused and joined to each other, the influence of the oxidation of the external electrode may reach the fusion bonded portion. In addition, the contact resistance at this joint can be reduced and stabilized. Also, the wire connection part of the joint fitting and the stranded wire end part of the wire are crimped by plastically deforming a pair of wire caulking pieces of the wire connection part. However, since at least the flat surface of the substrate portion, the root portion of both electric wire caulking pieces, and the tip of both electric wire caulking pieces are tightly fixed to each other, the contact resistance at the caulked portion can be reduced,
The stranded wire is less likely to be oxidized than the external electrode, so that the contact resistance at the caulked portion can be reduced and stabilized.

In order to solve the same problem, a liquid crystal display device according to a third aspect of the present invention uses the light source device according to the first aspect as a backlight of a liquid crystal display panel. .

According to the third aspect of the invention, since the light source device according to the first aspect is provided, a change in the total resistance value of the light source device with respect to the light source lamp is suppressed, and the characteristics of the light source lamp can be stabilized. The display performance can be stabilized as much as possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

Reference numeral 2 in the figure, which shows the liquid crystal display device 1 in an exploded manner, indicates a light source device used as a backlight of the liquid crystal display device 1. The light source device 2 includes a light source lamp 3
, A heater 4, an electric wire 5, and a fitting 6.

As the light source lamp 3, a low-pressure mercury vapor discharge lamp, for example, a cold cathode fluorescent lamp is used. The lamp 3 has a cold cathode electrode 12 mounted on each of the sealing portions at both ends of the bulb 11, a phosphor coating layer (not shown) formed on the inner peripheral surface of the bulb 11, and a predetermined amount of mercury therein. Argon,
It is formed by sealing a rare gas such as xenon.
The outer diameter of the valve 11 is as small as 2.6 mm. As shown in FIG. 1, the valve 11 is formed by integrally connecting straight pipe portions parallel to each other by three U-shaped bent pipe portions 11a to 11c, and is bent in a substantially W shape as a whole.

The heater 4 used for assuring the temperature at the time of starting the light source lamp 3 is a wire having a circular section of 0.18 mm in diameter and made of an Fe-Al alloy. This heater 4
Is provided, for example, wound along the outer surface of the bulb 11 of the light source lamp 3. In the configuration in which the heater 4 is wound around the bulb 11 in this manner, as compared with a case where a plate-like elongated heater is attached to the outer surface of the bulb 11, the mounting work is simpler and the wire diameter is small, so that the luminous flux is small. It is excellent in that it does not block much.

The heater 4 generates resistance heat by energizing the heater 4.
By evaporating the mercury in 1 and increasing the vapor pressure, the rising characteristics of the luminous flux can be improved. Therefore, the time from starting of the light source lamp 3 under a low temperature condition such as below freezing to stable lighting reaching a predetermined brightness can be shortened, and the startability of the lamp 3 can be improved.

An electric wire 5 for supplying electricity to the heater 4 is mechanically and electrically connected to the heater 4 through a fitting 6. This connection will be described with reference to FIG. Electric wire 5
Uses an insulated wire in which the stranded wire 5a is covered with an electrically insulating covering layer 5b. The joint fitting 6 is made of a conductive metal material, for example, Ni, which can be plastically deformed so as to be suitable for caulking and can maintain the deformed state.

The metal fitting 6 has one end connected to the heater connection part 15.
a flat board portion 15 used as a, a first wire connection portion 16 at the other end of the board portion 15, and a connection portion 16
And a second electric wire connection portion 17 provided between the heater connection portion 15a.

The first electric wire connecting portion 16 is formed by the other end of the substrate portion 15 and a pair of electric caulking pieces 18 bent from both side edges of the other end. First wire connection part 1
6, the terminal portion of the electric wire 5 is accommodated in the covering layer 5b, and each of the pair of electric wire caulking pieces 18 is covered with the covering layer 5b.
By digging it around the first
The terminal portion of the electric wire 5 is fixed to the electric wire connection portion 16 by caulking. This caulking is performed by an automatic machine. In addition, the 1st electric wire connection part 16 can be abbreviate | omitted in this invention.

The second winding connection portion 17 provided outside the heater connection portion 15a includes an intermediate portion of the board portion 15 located between the heater connection portion 15a and the first electric wire connection portion 16, and an intermediate portion of the intermediate portion. And a pair of electric wire caulking pieces 19 bent from both side edges. In the second electric wire connection part 17,
The stranded wire 5 protruding from the coating layer 5b of the electric wire 5 inside the wire 5
The terminal part of a is housed and crimped. The state before the electric wire caulking piece 19 is caulked is shown in FIG. 4D, and the terminal of the stranded wire 5a is sandwiched between a pair of electric wire caulking pieces 19 that are preliminarily bent substantially at right angles to the middle part of the substrate portion 15. The diameter of the terminal portion is slightly smaller than the width between the opposing surfaces of the wire caulking piece 19.

In this housed state, the pair of electric wire caulking pieces 19 are caulked by an automatic machine. As a result of this caulking, the pair of electric wire caulking pieces 19 are bent so that the tips 19a of the pair of electric wires are in a back-to-back state as shown in FIG. 4C and face the flat surface 15b of the intermediate portion. In this manner, the pair of electric wire caulking pieces 19 are bent into a substantially M-shape as a whole continuously with each other. Accordingly, the tip portion 19a cuts into the stranded wire 5a, and the stranded wire 5a is pressed against the flat surface 15b, and the stranded wire 5a is pushed away in the width direction of the substrate portion 15 so that the electric wire caulking pieces 19 Is pressed against the root portion 19b. Thereby, the tip of the stranded wire 5a is crimped to the second electric wire connection portion 17, and the stranded wire 5a and the fitting 6 are mechanically and electrically connected. In order to tightly crimp the stranded wire 5a in the region surrounded by the caulking piece 19 and the board portion 15, appropriately changing the size, the caulking shape, and the like of both electric wire caulking pieces 19 is the same as the twisting wire 5a. This is preferable in that the resistance value with the joint fitting 6 can be further reduced.

A terminal 4a of the heater 4 is welded by resistance welding to one flat surface of a heater connection portion 15a formed at one end of the substrate portion 15. This welding is performed after the end of the electric wire 5 is crimped to the joint fitting 6 as described above. With the terminal 4a of the heater 4 placed on the one surface, the two-dot chain line in FIG. The electrode A of the resistance welding machine shown by
It is carried out by applying a high current between the electrodes A and B while applying pressure between the electrodes A and B. Thereby, the terminal portion 4a and the heater connection portion 15a are joined by melting the metal structures of each other, and the terminal portion 4a of the heater 4 and the fitting 6 are mechanically and electrically connected. In FIG. 4B, reference numeral 4b denotes a portion crushed and welded by the pressure.

As shown in FIG. 2, the light source lamp 3 of the light source device 2 having the above-described configuration is accommodated in a casing 21 of the liquid crystal display device 1. The casing 21 has a shallow dish shape with an open top in FIG. 1, and is made of a metal such as aluminum or a synthetic resin such as polycarbonate. The opening of the casing 21 is an irradiation port, and the entire inner surface of the casing 21 forms a reflection surface, and light reflected by the reflection surface is directed to the irradiation port. One side wall of the casing 21 is provided with a pair of lamp leading notches 22.
Are provided, and a pair of electric wire leading notches 23 are provided between them.

A lamp holder 24 made of a heat-resistant rubber-like elastic material and having a lamp through hole 24a is fitted into each of the pair of lamp leading-out notches 22. Further, a lamp holder 25 made of a rubber-like elastic material and having a pair of lamp accommodating recesses 25a is mounted on the other side wall of the casing 21 facing the one side wall. Then, the light source lamp 3 inserts a pair of curved tube portions 11a and 11c of the bulb 11 which are arranged side by side into the lamp accommodating recess 25a, and inserts both ends of the bulb 11 into the lamp through holes 2a.
By passing the lamp through the lamp holder 4a, the lamp holder is supported by the lamp holders 24 and 25 and housed in the casing 21. The electric wires 5 electrically connected to both ends of the heater 4 wound around the light source lamp 3 are respectively passed through the electric wire lead-out notches 23 in a state where the light source lamp 3 is housed in the casing 21, and are shown in the drawing. The lighting circuit is not connected.

As shown in FIG. 2, the casing 21 is provided with a light diffusing and transmitting plate 26 for closing the irradiation port. The transmission plate 26 is made of an acrylic resin or the like, has a milky white color, and has a function of diffusing and transmitting light. On an outer surface (or an inner surface) of the light diffusion transmission plate 26, a thick portion 26a corresponding to a straight pipe portion of the bulb 11 is formed. These thick portions 26
“a” is formed such that the wall thickness gradually decreases as the distance from the straight pipe portion increases in the direction in which the straight pipe portions of the valve 11 are arranged. With this configuration, the maximum thickness portion of the thick portion 26a is positioned directly above the straight pipe portion of the valve 11, and the amount of transmitted light is reduced at this thickness portion, and the thickness increases as the distance from the maximum thickness portion increases. As the thickness decreases, the amount of transmitted light can be gradually increased. As a result, the uneven brightness over the entire surface of the light diffusion / transmission plate 26 is eliminated, and the brightness distribution can be equalized.

The liquid crystal display panel 2 is placed on the light diffusion transmission plate 26.
7 are superimposed. This liquid crystal display panel 27
The light diffusion transmission plate 26 has a liquid crystal display surface 27a.

In the liquid crystal display device 1 having the above configuration, when the light source lamp 3 is energized, the lamp 3 emits light in a shape along the bulb 11 of the lamp. Part of the light radiated from the lamp 3 is reflected by the reflection surface formed by the inner surface of the casing 21 and directed to the light diffusion transmission plate 26,
The remaining light goes to the light diffusion transmission plate 26. for that reason,
Almost all of the light emitted from the light source lamp 3 is emitted to the outside through the light diffusion transmission plate 26.

In such illumination, since the brightness distribution of the light diffusion transmission plate 26 becomes uniform based on the configuration of the light diffusion transmission plate 26 described above, the liquid crystal display illuminated from the back surface by the transmission plate 26 is used. The panel 27 is illuminated with uniform brightness over the entire surface, and becomes uniform in brightness.

In this case, when the ambient temperature is below freezing, the heater 4 attached to the outer surface of the valve 11
, The heater 4 generates heat, and the temperature inside the valve 11 can be increased. Therefore, the vapor pressure of mercury in the bulb 11 increases, and the rising characteristics of the luminous flux can be improved, so that the time from starting of the light source lamp 3 to reaching stable lighting can be shortened.

In the light source device 2 capable of guaranteeing the temperature at the time of starting at a low temperature, the terminal portion of the stranded wire 5b of the electric wire 5 and the terminal portion 4a of the heater 4 for heating the light source lamp 3 are as described above. Connected via a conductive joint fitting 6 as described above.

In this connection, the metal structure of the heater connection portion 15a of the joint fitting 6 and the terminal portion 4a of the heater 4 are fused and welded to each other by welding. Therefore, despite the fact that the heater 4 is easily oxidized, the influence of the oxidation does not affect the fusion bonding portion, and the contact resistance at this bonding portion can be reduced and stabilized.

Then, the second electric wire connection portion 17 of the joint fitting 6 is formed.
The end of the stranded wire 5 a of the electric wire 5 is fixed by plastically deforming the pair of electric wire caulking pieces 19 of the electric wire connection portion 17. Therefore, by the caulking, the tip portions 19a of the pair of electric wire caulking pieces 19 bite into the stranded wire 5a and press the stranded wire 5a against one flat surface 15b of the substrate portion 15 of the joint fitting 6, and the stranded wire 5a. Is pushed away in the width direction of the substrate portion 15 and the stranded wire 5 a can be pressed against the root portions 19 b of the caulking pieces 19. In this way, the terminal portion of the stranded wire 5a is brought into close contact with the flat surface 15b of the substrate portion 15, the base portion 19b of the electric wire caulking piece 19, and the tip portion 19a of the electric wire caulking piece 19, respectively.
Since a large contact area of the stranded wire 5a with respect to the wire connection portion 17 can be ensured, the contact resistance at the caulked portion can be reduced accordingly. Moreover, the stranded wire 5a of the electric wire 5 is
It is hard to oxidize compared to. Therefore, the contact resistance at the second electric wire connecting portion 17 for caulking the electric wire 5 to the joint fitting 6 can be reduced, and the contact resistance can be stabilized.

As described above, the total resistance in the current path to the heater 4 for assuring the temperature of the light source lamp 3 is suppressed to a small value, and the influence of oxidation and the like can be reduced, so that the resistance can be easily maintained. Therefore, the characteristics of the backlight light source lamp 3 whose temperature is guaranteed by the heater 4 can be stabilized, and the display performance of the liquid crystal display device 1 can be stabilized, and the quality of the device 1 can be improved.

FIG. 5 shows a second embodiment of the present invention. Since this embodiment is basically the same as the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the configuration and operation is omitted. The different parts will be described. The second embodiment shows an embodiment implemented as a light source device whose use is not limited to the light source device of the liquid crystal display device. The different portions from the first embodiment mainly use coil-shaped external electrodes instead of heaters. That was the point.

A light source lamp of a mercury vapor discharge lamp indicated by reference numeral 31 in FIG. 5 has an internal electrode 33 provided only at one end of a linear bulb 32, and an external lead wire 34 connected to this electrode 33 is connected to the one end. It has been pulled out. When an internal electrode is also provided at the other end of the bulb 32, an external lead wire connected to the internal electrode at the other end and the external lead wire 34 at the one end are connected by an electric wire or the like (not shown). The internal electrodes may have the same potential.

The outer surface of the bulb 32 of the lamp 31 has F
An external electrode 35 made of e-Al alloy or the like is wound, for example, along the outer surface of the bulb 32. This external electrode 3
5 is electrically connected to an external lead wire 34 via a high-frequency high-voltage application circuit (Hf lighting circuit) 36. By applying a high-frequency high voltage to the lighting device 2 in this configuration, a discharge is generated between the internal electrode 33 and the external electrode 35, thereby exciting a phosphor coating layer (not shown) on the inner surface of the bulb 32. The light source lamp 31 can emit light.

The insulated wire 5 and the external lead wire, which are wired between the high-frequency high-voltage applying circuit 36 and the external lead wire 34, are mechanically and electrically connected via the fitting 6. In this case, the external lead wire 34 is welded to the fitting 6 by resistance welding or the like. Further, both the stranded wire of the other insulated wire 5 and the terminal 35 a of the external electrode 35, which are wired between the high-frequency high-voltage applying circuit 36 and the external electrode 35,
Similarly, it is mechanically and electrically connected via a joint fitting 6. In this case, the external electrode 35 is welded to the fitting 6 by resistance welding or the like. Therefore, in the second embodiment, the heater connection portion 15a of the fitting 6 is to be read as an electrode connection portion. The configuration other than the points described above is the same as that of the first embodiment.

Therefore, in the second embodiment in which the external lead wire 34 connected to the internal electrode 33 is connected to the electric wire 5 and the external electrode 35 is connected to the electric wire 5 using the joint fitting 6 described above. Also, for the reason described in the first embodiment, the total resistance value of the energization path can be reduced and stabilized, so that the lighting characteristics of the light source lamp 31 can be stabilized.

FIG. 6 shows a third embodiment of the present invention. Since this embodiment is basically the same as the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the configuration and operation is omitted. The different parts will be described. This third embodiment shows an embodiment implemented as a light source device whose use is not limited to the light source device of the liquid crystal display device, and a different portion from the first embodiment is that an elongated plate-like external electrode is mainly used instead of a heater. This is the point used.

The light source lamp of the mercury vapor discharge lamp indicated by reference numeral 41 in FIG. 6 has a pair of band-shaped external electrodes 43 (only one of which is shown) on the outer surface of a linear bulb 42 and at a position corresponding to the radial direction. It is provided along the direction. At the opposite ends of both electrodes 34, a metal band 44 electrically connected to the external electrode 43 is wound around the end of the bulb 42, as represented by one external electrode 43. Is provided.
The metal band 44 as an end member of the external electrode 43 has a thin bare electric wire made of a single wire or the like. This bare electric wire is used as a terminal 45 of the external electrode 43. The external electrode 43, the metal band 44, and the terminal portion 45 are all made of an Fe-Al alloy or the like.

The terminal portion 45 of the external electrode 43 is electrically connected to a high-frequency high-voltage application circuit (Hf lighting circuit) 46 via the insulated wire 5. By applying a high-frequency high voltage to the lighting device 2 in this configuration, a discharge is generated between the two external electrodes 43, thereby exciting a phosphor coating layer (not shown) on the inner surface of the bulb 32, and
1 can emit light.

The terminal portion 45 and the electric wire 5 are mechanically and electrically connected to each other via the joint fitting 6. in this case,
The terminal portion 45 is welded to the fitting 6 by resistance welding or the like. Therefore, in this embodiment, the heater connection part 15a of the joint fitting 6 is to be read as an electrode connection part. The configuration other than the points described above is the same as that of the first embodiment.

For this reason, in the third embodiment in which the terminal portion 45 of the external electrode 43 and the electric wire 5 are connected by using the joint fitting 6 described above, the entire energization path is also connected for the reason described in the first embodiment. Since the resistance value can be reduced and stabilized, the lighting characteristics of the light source lamp 41 can be stabilized.

[0051]

The present invention is embodied in the form described above, and has the following effects.

According to the first aspect of the present invention, the terminal portion of the heater for heating the light source lamp is welded to the heater connection portion of the conductive joint fitting to reduce the contact resistance at the welding stop portion. Along with stabilizing, the terminal portion of the stranded wire of the electric wire that is energized to the heater is connected to the wire connection portion of the joint fitting having the substrate portion and the pair of wire caulking pieces, and the terminal portion has at least a flat portion of the substrate portion. Surface and the base of both wire caulking strips, and the tip of both wire caulking strips, respectively, and caulked them.The contact resistance at these caulked sections was also reduced and stabilized. It is possible to provide a light source device capable of suppressing a change in resistance value and stabilizing characteristics of the light source lamp.

According to the second aspect of the present invention, the terminal portion of the external electrode attached to the light source lamp is welded to the electrode connecting portion of the conductive joint fitting to reduce the contact resistance at the welding stop portion. In addition to reducing the size and stabilizing, the terminal portion of the stranded wire of the electric wire that is energized to the external electrode is attached to the substrate portion and the wire connecting portion of the joint fitting having the pair of wire caulking pieces. The crimped parts were closely adhered to the flat surface, the base of both electric wire caulking pieces, and the tip of both electric wire caulking pieces, and the contact resistance at these caulked parts was small and stable. It is possible to provide a light source device capable of suppressing the change in the total resistance value of the path and stabilizing the characteristics of the light source lamp.

According to the third aspect of the present invention, since the light source device according to the first aspect is provided, a liquid crystal display device having a stable display performance as the characteristics of the light source lamp of the light source device can be stabilized. Can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a liquid crystal display device including a light source device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal display device of FIG.

FIG. 3 is a plan view showing a light source device together with a casing of the liquid crystal display device of FIG. 1;

FIG. 4A is a side view showing a configuration of a connection portion between an electric wire and a heater of the light source device in FIG. 3; (B) is a top view which shows the structure of the connection part of the said electric wire and a heater. (C) is Z in FIG.
Sectional drawing of the electric wire connection part which follows the -Z line. (D) is FIG. 4 (C)
Sectional drawing shown in the state immediately before crimping the electric wire connection part of FIG.

FIG. 5 is a perspective view showing a light source device according to a second embodiment of the present invention.

FIG. 6 is a side view showing a part of a light source device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device 2 ... Light source device 3 ... Light source lamp 4 ... Heater 4a ... Heater terminal part 5 ... Electric wire 5a ... Electric wire stranded wire 5b ... Electric wire coating layer 6 ... Joint fitting 15 ... Board part 15a ... Heater connection part Or electrode connecting portion 15b: one flat surface of the substrate portion 17: electric wire connecting portion 19: electric wire caulking piece 19a ... distal end portion of electric wire caulking piece 19b ... base portion of electric wire caulking piece 27 ... liquid crystal display panel 31 ... light source lamp 35 ... external Electrode 41: Light source lamp 45: Terminal part of external electrode

Claims (3)

[Claims] 1. A light source lamp comprising a low-pressure mercury vapor discharge lamp, a heater provided along the outer surface of the light source lamp, a stranded wire electrically connected to a terminal portion of the heater, and covering the stranded wire. An electric wire having an electrically insulating covering layer, a substrate portion having a heater connection portion to which a terminal portion of the heater is connected by welding, and a bent portion from both side edges of the substrate portion at a position separated from the heater connection portion. It has a pair of electric wire caulking pieces provided so that the tips of each other face to one flat surface of the substrate portion in a back-to-back state,
An end portion of the stranded wire protruding from the coating layer is caulked in close contact with at least a flat surface of the substrate portion, a root side portion of the electric wire caulking piece, and a tip portion of the electric wire caulking piece. And a conductive fitting having a wire connection portion. 2. A light source lamp comprising a discharge lamp, an external electrode provided along an outer surface of the light source lamp, a stranded wire electrically connected to a terminal portion of the electrode, and an electric wire covering the stranded wire. An electric wire having a coating layer made of an insulating material; a substrate portion having an electrode connection portion to which a terminal portion of the external electrode is connected by welding; and a bent portion from both side edges of the substrate portion at a position separated from the electrode connection portion. Having a pair of electric wire caulking pieces provided so that the front ends thereof face one flat surface of the substrate part in a back-to-back state, the terminal part of the stranded wire protruding from the coating layer, At least a flat surface of the substrate portion, a base side portion of the two electric wire caulking pieces, and a conductive joint fitting having an electric wire connecting portion closely caulked to the tip portions of the two electric wire caulking pieces. What you did Characteristic light source device. 3. A liquid crystal display device using the light source device according to claim 1 as a backlight of a liquid crystal display panel.