JPH0955112A - Cold cathode discharge lamp unit, backlight and liquid crystal display device - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a cold cathode discharge lamp unit which has a small installation space, is easy to handle, and is excellent in workability of assembly, and a backlight and a liquid crystal display device using the same. SOLUTION: A strip-shaped flat cable 20 that is elastically deformable in the thickness direction is connected to at least one end of an elongated cold cathode discharge lamp 1, and the flat cable 20 is arranged substantially parallel to the lamp 1. It is a cold cathode discharge lamp unit characterized by being configured, a cold cathode discharge lamp and a flat cable are unitized, and since this unit maintains a constant shape, it is easy to handle,
The attachment process of the flat cable becomes easy when it is attached to a device, and since the flat cable is thin, it does not take up a large space and the installation space is small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode discharge lamp unit including a combination of an elongated cold cathode discharge lamp and wiring for supplying power to the lamp, a backlight using the same, and a liquid crystal display device.

[0002]

2. Description of the Related Art Recently, a side (edge) type backlight is used as a light source of a liquid crystal display device. In this type of backlight, an elongated cold cathode discharge lamp is arranged so as to face one side surface of a light guide plate arranged on the back surface of a liquid crystal display panel, and light emitted from the cold cathode discharge lamp is guided from the one side surface. The light is introduced into the light plate, reflected in the light guide plate, and emitted from a wide surface facing the back surface of the liquid crystal display panel, and the light emitted from this surface is applied to the back surface of the liquid crystal display panel. It is like this. In the sidelight type backlight as described above, since the cold cathode discharge lamp is arranged so as to face one side surface of the light guide plate, it is possible to reduce the thickness of the entire backlight and reduce the thickness of the entire liquid crystal display device. It is effective for shaping.

Recently, however, liquid crystal display devices have been required to be smaller and thinner, and accordingly, the light guide plate is made thinner, and the cold cathode discharge lamp, which must be smaller than the thickness of the light guide plate, is also thin. Tends to become. For example, our cold cathode discharge lamp with a lamp power of 2.3 W has a bulb diameter of 2.6 mm (outer diameter) and a bulb length of 220 mm.
It is set to mm (effective emission length 200 mm), which is extremely long and thin.

Such a cold cathode discharge lamp 1 has been conventionally used.
As shown in FIG. 14, power supply harnesses 90a, 90b are connected to both ends of the valve 10, and these harnesses 90a, 90b are made of electric wires (wiring cords) insulated and covered with silicon or vinyl, Connector 9
1 is connected.

Further, a so-called thin tube fluorescent lamp having an outer diameter of φ4.1 mm or less is mainly used as a light source for an LCD backlight, but it is required to have high brightness and further miniaturization (small space). ) There are conflicting items.

In order to increase the brightness, it is sufficient to increase the input current of the cold cathode lamp, but there is a problem in that the life is shortened and the input current is limited. Therefore, there is a method of arranging the cold cathode lamps in parallel with the axial direction of the two tubes.

Conventionally, for example, as shown in FIG. 15, cold cathode fluorescent lamps 1a and 1b are arranged in parallel with the axial direction of two tubes, and an insulating cap is provided at one end of the two tube axial directions. 26c is covered. Further, an insulating cap 26d is covered on the central portions of the cold cathode fluorescent lamps 1a and 1b arranged in parallel with the two tube axis directions.

The other ends of the two pipes in the axial direction are housed in the connector 91a. Further, from the insulating cap 26c, an electric wire 90c such as silicone clothing or vinyl is laid around from the outer lead wire of the cold cathode lamp, and the connector 91 is formed.
a.

[0009]

However, in such a cold cathode discharge lamp 1, the harnesses 90a and 90b are freely deformable, so that there is an advantage that the degree of freedom of the wiring around these harnesses 90a and 90b is high. In addition, since the harnesses 90a and 90b are freely deformed, there is a problem that the wiring process is troublesome. That is, when the cold cathode discharge lamp 1 is attached to one side surface of the light guide plate, the lamp 1 is attached to the chassis of the backlight through the lamp holder, but the harness 90a or 90b routed and wired is not provided. Since there is a problem such as hanging down, it is necessary to stop the predetermined place by some means, and the fastening structure of such a harness becomes complicated and the fastening process is troublesome.

Since the harness fastening process is troublesome, there is a problem that the work efficiency is not good when the lamp 1 is replaced. Further, in the case of the cold cathode discharge lamp 1 having a small outer diameter and elongated shape as described above, the harnesses 90a and 90b connected thereto have a predetermined voltage,
For example, an electric wire having a diameter of, for example, about 2.0 mm may be used in consideration of withstand voltage against a voltage of several hundreds of volts. In such a case, the harness becomes relatively thick with respect to the size of the lamp. . Therefore, when one of the harnesses 90a or 90b is routed along the valve 10 for wiring, there is a problem that a relatively thick harness becomes an obstacle, a large space is required, and wiring processing becomes complicated.

However, in the case of FIG. 15, the wire of silicone clothing or vinyl has to be thickened to a diameter of about 2 mm in order to secure pressure resistance.

Further, since the shape of FIG. 15 is not fixed, it can be bent freely, which makes it complicated to assemble it into a unit. The present invention has been made based on such a situation, and an object thereof is to combine a cold cathode discharge lamp and a wiring member for supplying power to this lamp into a unit, which requires a small installation space and is easy to handle. It is an object of the present invention to provide a cold cathode discharge lamp unit excellent in workability of assembly, a backlight using the same, and a liquid crystal display device.

Further, another object of the present invention is to provide a cold cathode fluorescent lamp which eliminates the above-mentioned problems and can be made into a small space (thinning and downsizing) and can be standardized (workability is improved). is there.

[0014]

According to a first aspect of the present invention, an external lead wire connected to the cold cathode is led out from an end portion of a tubular bulb in which the cold cathode is sealed, and is provided in the bulb. A cold cathode discharge lamp in which an ionizing medium containing a rare gas is enclosed; at least one end thereof is connected to the one external lead wire and is arranged substantially parallel to the bulb, and a band-shaped insulation elastically deformable in the thickness direction And a flat cable constituted by wiring a conductive wire on a film; and a cold cathode discharge lamp unit.

A second aspect of the present invention is the cold cathode discharge lamp unit according to the first aspect, wherein the cold cathode discharge lamp has an outer diameter of a bulb of 4.1 mm or less.
The invention of claim 3 is characterized in that the length of the flat cable is substantially equal to the length of the lamp.
Alternatively, the cold cathode discharge lamp unit according to claim 2.

Here, the total length of the lamp is the total length including the insulating cap and the base when the insulating cap and the base are attached to the lamp. The invention of claim 4 is
The external lead wire led out from the end portion of the valve is bent toward the center of the valve, and the end portion of the flat cable is connected to the bent end portion. The cold cathode discharge lamp unit according to any one of claims.

According to a fifth aspect of the present invention, the flat cable has a thickness of 0.1 mm or more and half or less of an outer diameter of the valve. It is a cold cathode discharge lamp unit.

According to a sixth aspect of the present invention, the width of the flat cable is equal to or more than half the outer diameter of the valve and is equal to or less than 10 mm, and the cooling according to any one of the first to fifth aspects. It is a cathode discharge lamp unit.

The invention of claim 7 is characterized in that the flat cable can be used by passing a current of 0.1 mA or more and 20 mA or less. It is the described cold cathode discharge lamp unit.

According to an eighth aspect of the present invention, the distance L between the valve and the flat cable arranged in parallel with the valve is L.
8. When the lamp current of the cold cathode discharge lamp is I, 0.1 ≦ L / I ≦ 100. 8. The cold cathode discharge lamp according to claim 1, wherein It is a unit.

According to a ninth aspect of the present invention, there is provided a tubular bulb in which a cold cathode is sealed, and an external lead wire connected to the cold cathode and led out from an end portion of the bulb. Two or more cold cathode lamps arranged so as to be substantially parallel to each other; an external reliance having a substrate on which a wiring pattern is formed and led out from one or both tube ends of the discharge lamp. -A flat cable in which a wire is connected to a wiring pattern and the substrate is located substantially in the center of each discharge lamp and arranged substantially parallel to the tube axis direction of the bulb.
Bull and; are provided.

The invention of claim 10 is characterized in that the flat cable according to claim 9 is at least longer than the emission length of the discharge lamp. The invention according to claim 11 is the discharge lamp according to claim 9 or 10, wherein the outer diameter of the discharge lamp is d [mm], the width of the flat cable is a [mm], and the thickness is b [mm].
When the distance between the discharge lamp and the flat cable is l [mm], 0.1d ≦ a ≦ 1.1d and l ≦ 0.5d
Further, it is characterized in that it is configured so as to satisfy the condition of b ≦ 0.5a.

The twelfth aspect of the invention is the ninth to eleventh aspects.
The flat cable described in any one of the above is characterized in that the substrate is made of glass epoxy resin or ceramics, and the wiring pattern is made of copper foil.

The thirteenth aspect of the present invention is characterized in that the flat flat cable according to any of the ninth to twelfth aspects has a substance which reflects visible light adhered to the surface thereof. A fourteenth aspect of the present invention is characterized in that the flat cable of the thirteenth aspect has a wedge-shaped cross section inwardly curved.

A fifteenth aspect of the invention is characterized in that the flat cable according to any one of the first to fourteenth aspects is entirely or partially reinforced.

According to a sixteenth aspect of the present invention, there is provided the cold cathode discharge lamp unit according to any one of the first to fifteenth aspects; a reflector for reflecting light emitted from the cold cathode discharge lamp; A light guide plate which introduces the light reflected by the reflector and the light emitted from the cold cathode discharge lamp unit from the side surface and emits the light from the other surface.

According to a seventeenth aspect of the present invention, a cold cathode discharge lamp unit according to the ninth aspect; a reflector for reflecting the light emitted from the cold cathode discharge lamp unit; and the light reflected by the reflector, A light guide plate that introduces light emitted from the cold cathode discharge lamp unit and emits the light from another surface, and the bulb outer diameter of the discharge lamp is φ4.1 m.
The width of the discharge lamp unit in which two or more discharge lamps are arranged in parallel is 0.5 to 2.m below the thickness of the light guide plate.
It is characterized by being 0 times.

An eighteenth aspect of the present invention is characterized by including the backlight according to the sixteenth or seventeenth aspect; and a liquid crystal display unit illuminated by the backlight.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the first embodiment shown in FIGS. FIG.
Is a cold cathode fluorescent lamp 1, and an elongated straight tube type bulb 10.
It has. The bulb 10 is, for example, an elongated lead glass tube with an outer diameter of 2.6 mm (inner diameter of 2.0 mm) and a total length of 220 mm (effective emission length of 200 mm). A phosphor layer that is excited to emit visible light, for example, a phosphor layer made of a three-wavelength light emitting phosphor is formed. The three-wavelength light-emitting phosphor may be, for example, Y ₂ O as a red phosphor.
₃ : Eu, LaPO ₄ : Ce, Tb as green phosphor,
BaMgAl ₁₄ O ₂₃ : Eu is used as a blue phosphor.

Cold cathodes 11 are sealed at both longitudinal ends of the bulb 10, as shown in FIG. The cold cathode 11 is configured by joining a rod-shaped or cylindrical cold-cathode body 13 made of nickel Ni or the like to the electrode shaft 12. External lead wires 14a and 14b (only one of which is shown) are integrally or separately connected to the electrode shafts 12 at both ends of the valve.
4a and 14b are led out from the end of the valve 10.

The valve 10 is filled with a predetermined amount of mercury and a mixed rare gas of argon Ar and neon Ne at a predetermined pressure as an ionizing medium. The filling pressure of the mixed rare gas is about 100 Torr.

The cold cathode fluorescent lamp 1 having such a structure is
When the lamp current is 5 mA, the lamp voltage is 475 Vrms,
Lamp power 2.3W, positive column potential gradient 1.78V
It is set to rms / mm.

A flat cable 20 is connected to the cold cathode fluorescent lamp 1 as a power supply wiring. That is, the flat cable 20 is connected to one of the external lead wires 14a of the lamp 1, and the flat cable 20 has a long strip-shaped insulating film to which conductive wires (including conductive print and conductive foil) are wired. Is configured,
It is arranged along the lamp 1.

A detailed structure of an example of the flat cable 20 is shown in section in FIG. In FIG. 4, reference numeral 21 denotes a polyimide resin film serving as a base insulating film, and a conductive foil 22 made of a metal such as copper is laminated and adhered to the base insulating film 21 via an adhesive. A polyester resin film 23, which serves as a cover insulating film, is laminated and adhered to 22 via an adhesive.

Flat cable 2 having such a laminated structure
0 is less than half of the outer diameter of the valve 10 when the wall thickness t is 0.1 mm or more, and is 0.135 mm in the case of FIG. In addition, the width W of the flat cable 20 depends on the valve 10.
It is not less than half the outer diameter and not more than 10 mm, and in this embodiment, it is formed to be 6 mm. The flat cable 20 as described above has an overall length substantially equal to the lamp length, and is formed longer than the effective light emission length of the lamp 1. The lamp length means insulating caps 26a and 26b described later.
It is the length including.

The flat cable 20 having such a structure
Can be elastically deformed in the thickness direction, but is hard to be deformed in the width direction, and therefore has a certain degree of hardness, that is, rigidity, and maintains a long strip shape.

One end of the strip-shaped flat cable 20 is bent in an L-shape in the width direction, and a land portion 24a is formed at the bent tip. And
One external lead wire 1 led out from one end of the valve 10.
As shown in FIG. 2, 4a is bent in a U-shape toward the center of the valve, and this U-shaped bent tip is joined to the land 24a of the flat cable 20 by solder 25.

At one end of the valve 10, the valve shown in FIG.
As also shown in FIG. 3, an insulating cap 26a made of silicone rubber or the like is covered, and the insulating cap 26 is covered with an adhesive 27 such as a silicone adhesive.
Of the flat cable 20 and the end of the flat cable 20. The insulating cap 26 is formed on the external lead wire 14a.
It also hides the exposure of the land portion 24a.

With such a joint structure, the flat cable 20 is electrically connected to the lamp 1 and is mechanically coupled to the lamp 1 through one end portion thereof. Therefore, the lamp 1 and the flat cable 20 are connected. Are integrated, so-called unitized.

In this case, the flat cable 20 is arranged substantially in parallel with the lamp 1, and the L-shaped end formed at one end of the flat cable 20 is mechanically joined to the end of the bulb 10. The lamp 1 and the flat cable 20 are separated by a predetermined distance L. In the case of the present embodiment, this distance L is represented by the shortest distance in the oblique direction, and is the cold cathode. When the lamp current of the fluorescent lamp 1 is I, 0.1 ≦ L / I ≦ 100. Specifically, in this embodiment, L = 4 mm.

A harness 90 is directly attached to the other external lead wire 14b (not shown) led out from the other end of the lamp 1.
a is connected. Although not shown, these external lead wires 14b and harness 90a are joined by solder,
This joint is covered with an insulating cap 26a made of another silicone rubber or the like to prevent exposure.

At the other end of the flat cable 20, another land portion 24b is formed as shown in FIG. Another harness 90b is joined to the land portion 24b by solder 28. The soldered portion is covered with an insulating tape 29 wound around the end of the flat cable 20.

The harness 90a connected to the other end of the lamp 1 and the harness 90b connected to the end of the flat cable 20 are connected to the connector 91. The connector 91 is connected to the high frequency power supply device 2 shown in FIG. 1, and the high frequency power supply device 2 supplies high frequency power of about 50 kHz to the lamp 1.

The operation of the cold cathode discharge lamp unit having such a configuration will be described. When high frequency power having a frequency of 50 kHz and a voltage of about 1200 V (rms) is supplied from the high frequency power supply device 2, the high frequency voltage is generated between the cold cathodes 11 and 11 via the connector 91, the pair of harnesses 90a and 90b, and the flat cable 20. Is applied. Therefore, a discharge is generated between the cold cathodes 11 and the mercury and the rare gas are ionized, and mainly ultraviolet rays are emitted. This ultraviolet ray is converted into visible light by the phosphor layer,
It is discharged to the outside through the wall of the valve 10.

The cold cathode discharge lamp unit having the above structure is
The flat cable 20 is arranged in parallel in the longitudinal direction along the elongated cold cathode fluorescent lamp 1, and one end of the flat cable 20 is electrically and mechanically joined to one end of the lamp 1, so that the lamp 1 and the flat cable 20 are connected. Are integrated. Moreover, the flat cable 20 can be elastically deformed in the thickness direction but is not deformed in the width direction, and thus has a certain degree of rigidity. Therefore, the flat cable 20 does not hang down, so that the lamp 1 as shown in FIG. It is possible to form a unit of a certain shape in cooperation with.

In the case of FIG. 1, the cold cathode discharge lamp unit has a generally U-shaped elongated shape, and this shape is maintained even when the cold cathode discharge lamp unit is lifted.
Therefore, when handling this cold cathode discharge lamp unit, it is easy to handle because the shape is constant.

Further, the flat cable 2 serving as wiring means
Since 0 is flexible in the thickness direction, it causes some bending, but it is not so soft that it droops largely due to its own weight. Therefore, when the cold cathode discharge lamp unit is attached to the backlight chassis 33 described later, the flat cable 2
0 will never get in the way.

In the cold cathode fluorescent lamp 1 of the above embodiment, the bulb 10 has an outer diameter of 4.1 mm or less, specifically 2.6 mm. When such harnesses 90a and 90b are used, the diameter of the harness becomes relatively thicker and the space occupied by the harness becomes larger than that of the lamp. However, when the flat cable 20 is used, the flat cable 20 has a thin strip shape. Since it has a small space, it occupies a small space.

Further, since the length of the flat cable 20 is made substantially equal to the lamp length, the flat cable 20 does not get in the way. If the flat cable 20 is too short, a thick harness 90b must be added to the flat cable 20, but if the light emitting length is at least longer, the harness will not interfere even if a thick harness is added.

Then, as in the above embodiment,
One external lead wire 1 led out from the end of the valve 10.
4a is bent toward the center of the valve, and the land portion 24a of the flat cable 20 is connected to this bent end, so that the end of the flat cable 24a does not significantly project from the end of the valve, and the flat cable 2
The length of 0 can be set to the length of the lamp or less (including the end portion of the insulating cap 26a).

Furthermore, the thickness t of the flat cable is set to 0.
1mm or more and half or less of the valve outer diameter, specifically t =
Since the thickness is 0.135 mm, the strength of the flat cable 20 is ensured, the flat cable 20 does not become thicker than necessary, has appropriate flexibility, and can be elastically deformed as necessary.

Since the width W of the flat cable is set to be more than half the outer diameter of the valve and 10 mm or less, specifically 6 mm,
A predetermined strength is secured, deformation in the width direction is prevented, and the width does not become wider than necessary.

Since the flat cable 20 can pass a current of 0.1 mA or more and 20 mA or less by regulating the cross-sectional area of the conductive foil 22, it is effective as a power supply wiring means for a small cold cathode discharge lamp. is there.

Since the distance L between the lamp 1 and the flat cable 20 is set to 0.1≤L / I, no leakage current from the lamp 1 is generated. That is, if the bulb 10 and the flat cable 20 are too close to each other, the positive column may be pulled by the flat cable during discharge and the positive column may be bent, or electrons may be pulled by the flat cable to cause leakage current. If 0.1 ≦ L / I, such a problem can be suppressed. Then, by appropriately securing the separation dimension L between the lamp and the flat cable, the positions of the lamp and the flat cable are not constrained, and the degree of freedom of assembly is increased. Moreover, since L / I ≧ 100, the separation dimension L between the valve and the flat cable does not become too large, and the entire space can be reduced.

7 and 8 show an example in which the cold cathode discharge lamp unit of the above-described embodiment is used as a backlight light source of a liquid crystal display device. That is, these FIG. 7 and FIG.
In the figure, 30 is a backlight and 40 is a liquid crystal display panel.

The backlight 30 comprises a light guide plate 31, the cold cathode discharge lamp unit arranged on one side of the light guide plate 31 and a reflector 32 surrounding the lamps 1. The light guide plate 31, The cold cathode discharge lamp unit and the reflector 32 are attached to the chassis 33 shown in FIG.

The light guide plate 31 is made of a transparent or milky white light transmissive material such as acrylic resin and is formed in a rectangular flat plate shape. The cold cathode discharge lamp unit is arranged at one end of the light guide plate 31 so as to face the end surface of the light guide plate 31. In this lamp unit, the lamp 1 substantially faces the end surface of the light guide plate 31, and the cold cathode fluorescent lamp 1 is covered with a reflector 32. The reflector 32 is made of metal, resin, or the like, and has a substantially gutter-shaped cross section having a quadratic curve and extending along the tube axis direction of the cold cathode fluorescent lamp 1. The light emitted from the cold cathode fluorescent lamp 1 is reflected by the reflection surface formed on the inner surface of the reflector 32 and directed toward the end surface of the light guide plate 31.

A reflection plate or a reflection sheet 35 is provided on the lower surface of the light guide plate 31, and the reflection plate sheet 35 is provided.
Reflects the light introduced into the light guide plate 31 and directs it toward the upper surface (front surface) side. A light diffusing plate or light diffusing sheet 36 made of acrylic resin or the like and having a milky white color is provided on the upper surface of the light guiding plate 31, and the light diffusing plate 36 diffuses the light emitted from the light guiding plate 31 and makes it uniform. The brightness distribution is controlled so that the uneven brightness is eliminated.

The flat cable 20 in the cold cathode discharge lamp unit faces the lower surface of the light guide plate 31. That is, the cold cathode discharge lamp unit is fixed to the chassis 33, but the cold cathode fluorescent lamp 1 of this unit is housed in the reflector 32 along the axial direction of the reflector 32 having a gutter shape. Therefore, the flat cable 20 is also arranged along the axial direction of the reflector 32. However, since the flat cable 20 is separated from the lamp 1 by the dimension L, it is provided outside the reflector 32, and this installation position is opposed to the lower surface of the end portion of the light guide plate 31.

With this arrangement, the cold cathode discharge lamp unit is inserted and removed along the axial direction of the reflector 32. In this case, since the flat cable 20 does not hang down, it does not interfere with the inserting and removing work. Therefore, the insertion / removal work is easy, and it is not necessary to fix the middle portion of the flat cable 20 particularly. Even if the middle portion is fixed, it can be stopped with a simple structure.

As a result, the cold cathode discharge lamp unit can be easily attached and detached, and the replacement work can be easily performed.
The backlight 30 having such a configuration is installed on the back surface of the liquid crystal display panel 40, and thus the backlight 30 and the liquid crystal display panel 40 form a liquid crystal display device.

The present invention is not limited to the above-mentioned first embodiment. That is, in the case of the first embodiment shown in FIG. 1, one end of the flat cable 20 is electrically and mechanically joined to one end of the lamp 1, and the flat cable 20 and the other end of the lamp 1 are separated from each other. Although it is a free end, the flat cable 20 and the other end of the lamp 1 may be electrically and mechanically joined to each other as shown in FIG. That is, the flat cable 20 and the lamp 1 are joined to each other at both ends thereof, and are separated from each other at the middle portion, and have an elongated rectangular shape as a whole.

In this case, as shown in FIG. 9 (A),
A terminal terminal may be provided at the end of the flat cable 20 to integrally form the connector portion 95, or as shown in FIG. 9B, harnesses 90a and 90b may be provided at the end of the flat cable 20, respectively. You may connect, and you may connect the connector 91 to these harnesses 90a and 90b.

Furthermore, the present invention may be configured as shown in FIG. In the example shown in FIG. 10, the end portion of the flat cable 20 is bent into a Z shape in the thickness direction, and the bent tip portion is electrically and mechanically joined to one end of the lamp 1. Even in this case, the lamp 1 and the flat cable 20 can be formed in parallel with each other while keeping a predetermined distance therebetween. However, in this case, it is necessary to keep the end portion of the flat cable 20 bent in the Z direction in the thickness direction, and for this purpose, it is necessary to increase the rigidity of the flat cable 20.

In order to increase the rigidity of the flat cable 20, it is possible to select a material for the insulating film and use a hard film, or to increase the wall thickness to reduce the flexibility. In this case, the reinforcing member 70 is laminated with an adhesive as shown by an imaginary line in FIG. The reinforcing member 70 may be a plate material, a sheet material, a film material, or the like. Specifically, for example, a film made of polyethylene terephthalate having a thickness of about 350 μm is bonded with an adhesive. With this configuration, the rigidity is higher than the position where the reinforcing member 70 is not provided and the position where the reinforcing member 70 is not provided is more difficult to bend, so that the knot is formed, and thus the bent shape can be obtained.

The reinforcing member 70 as described above is shown in FIG.
Can also be applied to the flat cable 20 of each embodiment shown in FIG. 9 and used to increase the rigidity to some extent.
In the above embodiment, the cold cathode fluorescent lamp 1 is
Although the fluorescent lamp has the fluorescent material layer formed on the inner surface of the bulb 10, it can be implemented with a rare gas discharge lamp that does not use the mercury and fluorescent material layers.

Further, the conductive wire formed on the flat cable 20 is not limited to the conductive foil 22, and may be a conductive wire or a printed wiring. Next, a fourth embodiment of the present invention will be described with reference to FIG. 41a, 41b
Are cold cathode discharge lamps arranged in parallel. Each cold cathode discharge lamp 41a, 41b has a diameter of 2.6 m
m, lamp length: 220 mm, lamp voltage: 475 V, lamp power: 2.3 W, positive column potential gradient: 1.78 V / mm
It is.

Between the cold cathode discharge lamps 41a and 41b, a flat cable 42 formed by using a resin such as polyimide or polyester as a substrate is interposed. The flat cable 42 has a total length of 227 mm, a substrate thickness of 50 μm, a copper foil thickness of 35 μm, and a coverlay thickness of 25 μm. Cold cathode discharge lamp 41
An external lead wire connected to the cold cathode and connected to the wiring pattern of the flat cable 42 is led out to one end side of each of a and 41b, and an insulating cap is attached to this lead wire. 42a and 42b are covered. The flat cable 42 is reinforced by adhering a resin such as polyethylene terephthalate or glass epoxy or a metal such as aluminum to the whole or a part of the flat cable 42.

Further, the cold cathode discharge lamps 41a, 41b
The insulating caps 42c and 42d are also covered on the other end of the. Insulation caps 42a-42d are 3.5x3x6
It has a size of mm. This insulating cap 42a
And 42b, and between the insulating caps 42c and 42d, a flat cable 42 is interposed. And
One end of a harness 43 is soldered to the terminal of the wiring pattern on the other end of the flat cable 42. The other end of the harness 43 is connected to the connector 44.

The other ends of the cold cathode discharge lamps 41a and 41b are connected to the cold cathode on the other end and are insulated cap 42.
It is connected to the connector 44 via a harness 45 as an external lead wire derived from the cables c and 42d.

By the way, the cold cathode discharge lamps 41a, 41
The distance between b and the flat cable 42 is set to 0.5 mm. A wiring pattern is formed on the substrate of the flat cable 42, for example, with a copper foil or the like. A current of 0.1 to 20 A flows through the cold cathode discharge lamp.

The bulb outer diameter of the discharge lamps 41a and 41b is φ4.1 mm or less, and the inner surface of the bulb is coated with a phosphor. The width d of the cold cathode discharge lamp unit is
It is designed to be 0.5 to 2.0 times the thickness of the light guide plate of the backlight.

As described above, according to the fourth embodiment of the present invention, the flat cable 42 is placed between the two discharge lamps.
Since it is arranged so as to intervene, it is possible to reduce the space even for a unit provided with a plurality of lamps, and it is possible to achieve high efficiency (high brightness).

Further, since the shape is stable, it can be easily assembled into the unit and the workability can be improved. Next, a fifth embodiment of the present invention will be described.
The block diagram of the fifth embodiment of the present invention is the same as FIG.

The outer diameter of the discharge lamps 41a and 41b is set to d [m
m], two or more flat cables 42 arranged in parallel
Where a is [mm], the thickness is b [mm], and the distance between the discharge lamp and the flat cable 42 is l [mm], 0.1d ≦ a ≦ 1.1d and l ≦ 0.5d And
The dimensions satisfy b ≦ 0.5a.

As described above, according to the fifth embodiment of the present invention, since the flat cable 42 is provided between the discharge lamps, the space can be further reduced.
Furthermore, since the two discharge lamps are arranged in parallel,
High efficiency (high brightness) is possible, and the light from the lamp can be effectively utilized for entering the light guide plate of the unit.

The substrate of the flat cable 42 of the fifth embodiment described above may be made of glass epoxy resin, ceramics or the like. Furthermore, the above-mentioned fifth
The flat cable of the above embodiment may be attached by vapor-depositing or applying a substance of aluminum or metal oxide that reflects visible light on the surface.

Next, a sixth embodiment of the present invention will be described with reference to FIGS. The description of the same configurations as those of the fourth and fifth embodiments will be omitted. In this embodiment, the flat cable 42 has a wedge-shaped flat shape in which the cross section is warped inward, and this surface acts as a reflecting surface to efficiently reflect light in the apex side direction of the wedge. As described above, according to the sixth embodiment of the present invention, higher efficiency (higher brightness) can be achieved, and the light from the lamp is effectively reflected to the light guide plate of the unit.

[0079]

As described above, according to the invention of claim 1, a flat cable which is flexible in the thickness direction but is not easily deformed in the width direction is used as the elongated cold cathode discharge lamp. Since they are connected separately, the cold cathode discharge lamp and the flat cable are unitized with a predetermined long shape. This unit maintains a constant shape, making it easy to handle and the flat cable hangs down. There are no problems such as the above, and the attachment processing of the flat cable is easy when it is attached to equipment. Moreover, since the flat cable is thin, it does not take up a large space even if it is placed in parallel with the valve.
The installation space is small.

According to the second aspect of the present invention, when the bulb outer diameter of the cold cathode discharge lamp is 4.1 mm or less, the flat cable can be used to reduce the entire size and the installation space. You can

According to the invention of claim 3, the length of the flat cable is made substantially equal to the length of the lamp, so that the flat cable does not get in the way. According to the invention of claim 4, the external lead wire led out from the end portion of the valve is bent toward the center of the valve, and the end portion of the flat cable is connected to the bent end portion. It can be less than or equal to the lamp length.

According to the invention of claim 5, since the thickness of the flat cable is 0.1 mm or more, the strength of the flat cable is secured, and since it is less than half the outer diameter of the valve, the flat cable does not become thick, and It has appropriate flexibility and can be elastically deformed if necessary.

According to the invention of claim 6, since the width of the flat cable is set to be half or more of the outer diameter of the valve, a predetermined strength can be secured and deformation in the width direction is prevented.
Since the width is 0 mm or less, the width does not become larger than necessary.

According to the seventh aspect of the invention, the flat cable can pass a current of 0.1 mA or more and 20 mA or less, and is effective as a power supply wiring means for a small cold cathode discharge lamp.

According to the invention of claim 8, the distance L between the lamp and the flat cable is set to 0.1 ≦ L / I, so that no leakage current from the lamp occurs. According to the invention of claim 9, it is possible to reduce the space.

According to the tenth aspect of the invention, it is possible to achieve high efficiency (high brightness). Further, since the FPC length is longer than the light emitting portion of the lamp, the light from the lamp can be effectively used.

According to the eleventh aspect of the invention, it is possible to achieve high efficiency (high brightness). Further, the light from the lamp can be effectively used for entering the light guide plate of the unit.

According to the twelfth aspect of the invention, it is possible to reduce the space. Also, the opportunity strength of the fluorescent lamp can be improved. According to the thirteenth aspect, it is possible to reduce the space.

According to the fourteenth aspect of the invention, it is possible to reduce the space. According to the invention of claim 15,
Since the above flat cable is wholly or partially reinforced, its strength is increased and its rigidity is increased to keep the flat cable itself in a good shape.

According to the sixteenth aspect of the present invention, the cold cathode discharge lamp unit can be easily combined with the light guide plate. In this case, since the flat cable maintains the predetermined shape, the flat cable does not get in the way. The fastening process is easy and the desorption work can be done efficiently. Also, replacement work becomes easy.

According to the seventeenth aspect of the present invention, high efficiency (high brightness) can be realized. Further, the light from the lamp can be effectively used for entering the light guide plate of the unit. According to the eighteenth aspect of the invention, it is possible to provide a liquid crystal display device that makes the most of the advantages of the cold cathode discharge lamp unit and the backlight.

[Brief description of drawings]

FIG. 1 is a perspective view of a cold cathode discharge lamp unit showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a connection portion between the cold cathode fluorescent lamp and the flat cable of the same embodiment.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of the flat cable of the same embodiment.

5A to 5C are explanatory views showing the structure of the connecting portion between the cold cathode fluorescent lamp and the flat cable in the order of the connecting work.

6A and 6B are explanatory views showing the structure of the connection portion of the flat cable and the harness in the order of connection work.

FIG. 7 is an exploded perspective view of a cold cathode fluorescent lamp unit used as a backlight of a liquid crystal display device.

FIG. 8 is a sectional view of the liquid crystal display device.

FIG. 9A is a perspective view of a cold cathode discharge lamp unit showing a second embodiment of the present invention, and FIG. 9B is a cold cathode discharge lamp unit showing a third embodiment of the present invention. FIG.

FIG. 10 is a perspective view of a cold cathode discharge lamp unit showing a third embodiment of the present invention.

FIG. 11 is a perspective view of a cold cathode discharge lamp unit according to fourth to seventh embodiments of the present invention.

FIG. 12 is a perspective view of a cold cathode discharge lamp unit according to an eighth embodiment of the present invention.

FIG. 13 is a cross-sectional view of a conductor.

FIG. 14 is a perspective view of a conventional cold cathode fluorescent lamp.

FIG. 15 is a perspective view of a conventional cold cathode fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cold cathode fluorescent lamp 2 ... High frequency power supply device 10 ... Bulb 11 ... Cold cathode 14a, 14b ... External lead wire 20 ... Flat cable 21 ... Base insulating film 22 ... Conductive foil 23 ... Cover insulating film 26a, 26b ... Insulation Cap 30 ... Backlight 31 ... Light guide plate 32 ... Reflector 90a, 90b ... Harness 91 ... Connector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Kobayashi 4-3-1, Higashi-Shinagawa, Shinagawa-ku, Tokyo Within Toshiba Litec Co., Ltd. (72) Masami Takagi 4-3-1, Higashi-Shinagawa, Shinagawa-ku, Tokyo Issue Toshiba Lighting & Technology Corporation

Claims (18)

[Claims] 1. An external lead wire connected to the cold cathode is led out from an end of a tubular bulb in which the cold cathode is sealed, and an ionizing medium containing a rare gas is enclosed in the bulb. A cold cathode discharge lamp; at least one end of which is connected to the one external lead wire and arranged substantially in parallel with the bulb, and a conductive wire is wired in a band-shaped insulating film that is elastically deformable in the thickness direction A cold cathode discharge lamp unit comprising: a flat cable; 2. The cold cathode discharge lamp unit according to claim 1, wherein the cold cathode discharge lamp has a bulb outer diameter of 4.1 mm or less. 3. The cold cathode discharge lamp unit according to claim 1, wherein a length of the flat cable is substantially equal to a length of the lamp. 4. The outer lead wire led out from the end portion of the valve is bent toward the center of the valve, and the end portion of the flat cable is connected to the bent end portion. The cold cathode discharge lamp unit according to claim 3. 5. The flat cable has a thickness of 0.1.
5. The cold cathode discharge lamp unit according to claim 1, wherein the cold cathode discharge lamp unit has a diameter of not less than mm and not more than half the outer diameter of the bulb. 6. The cold cathode discharge lamp unit according to claim 1, wherein the width of the flat cable is not less than half the outer diameter of the bulb and not more than 10 mm. 7. The cold cathode discharge according to claim 1, wherein the flat cable can be used by passing a current of 0.1 mA or more and 20 mA or less. Lamp unit. 8. The distance L between the bulb and the flat cable arranged in parallel with the bulb is 0.1 ≦ L / I ≦ 100, where I is the lamp current of the cold cathode discharge lamp. The cold cathode discharge lamp unit according to any one of claims 1 to 7, wherein 9. A tubular bulb having a cold cathode sealed therein and an external lead wire connected to the cold cathode and led out from an end portion of the bulb, and the tube axial directions of the bulb are substantially parallel to each other. And two or more cold cathode lamps arranged as described above; a substrate on which a wiring pattern is formed, and an external lead wire led from one or both tube ends of the discharge lamp is wired. A flat cable connected to the pattern and arranged substantially parallel to the tube axis direction of the bulb so that the substrate is located substantially in the center of each discharge lamp. Cold cathode discharge lamp unit. 10. The cold cathode fluorescent lamp according to claim 9, wherein the flat cable is at least longer than the emission length of the discharge lamp. 11. The outer diameter of the discharge lamp is d [mm], the width of the flat cable is a [mm], the thickness is b [mm], and the distance between the discharge lamp and the flat cable is 1 [mm]. When 0.1d ≦ a ≦ 1.1d and l ≦ 0.5d and
The cold cathode fluorescent lamp according to claim 9, wherein the cold cathode fluorescent lamp is configured to satisfy the condition of b ≦ 0.5a. 12. The flat cable has a substrate formed of glass epoxy resin or ceramics, and the wiring pattern is formed of copper foil. Cold cathode discharge lamp. 13. The fluorescent lamp according to claim 9, wherein a material that reflects visible light is attached to the surface of the flat flat cable. 14. The cross-sectional shape of the flat cable is
14. The cold cathode discharge lamp according to claim 13, wherein the cold cathode discharge lamp has a wedge shape that is curved inward. 15. The cold cathode discharge lamp unit according to claim 1, wherein the flat cable is totally or partially reinforced. 16. The cold cathode discharge lamp unit according to claim 1, a reflector for reflecting the light emitted from the cold cathode discharge lamp, and a reflector for reflecting the light emitted from the cold cathode discharge lamp. And a light guide plate which introduces light and light emitted from the cold cathode discharge lamp unit from a side surface and emits the light from another surface. 17. The cold cathode discharge lamp unit according to claim 9, a reflector for reflecting the light emitted from the cold cathode discharge lamp unit; the light reflected by the reflector and the cold cathode discharge lamp unit. The discharge lamp has a light guide plate that introduces light emitted from the other surface and emits the light from another surface.
A backlight characterized in that the width of a discharge lamp unit in which two or more discharge lamps are arranged in parallel is 0.5 to 2.0 times the thickness of the light guide plate. 18. A liquid crystal display device comprising: the backlight according to claim 16; and a liquid crystal display unit illuminated by the backlight.