JP2004302048A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size and thickness of a liquid crystal display device disposed with a linear light source at one side end surface of a light guide plate. <P>SOLUTION: The liquid crystal display device is equipped with the light guide plate 5 which has a nearly rectangular shape having a slanted rear surface so as to be made thinner in plate thickness from one side end toward the other side end, the linear light source 41 which is disposed along the surface of the plate thickness on one end side of the light guide plate 5, and lead wires 44c which are respectively connected to both ends of the linear light source 41. The light guide plate 5 is so installed that the spacing between the rear surface of the light guide plate 5 and the bottom wall of a housing expands as its plate thickness decreases. The lead wires 44c exist partly within the spacing, are installed along the other side end of the light guide plate 5 and are led out to the rear surface side of the housing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a wiring structure of an illumination unit is improved to reduce the size.
[0002]
[Prior art]
A backlight used in a liquid crystal display device uses a small-diameter fluorescent tube such as a cold cathode or hot cathode tube as a light source, and is generally classified into an edge type and a direct type.
[0003]
The edge type backlight has a structure in which a linear light source composed of a small-diameter fluorescent tube is disposed on a side surface of a light guide plate, and light from this light source is guided to a surface of a liquid crystal panel. The light from the linear light source provided in the lamp chamber is diffused and applied to the liquid crystal panel through the diffusion plate.
Among them, the edge type backlight can arrange the linear light source on the side surface of the light guide plate, so that the installation space for the linear light source can be saved and the size and thickness can be easily reduced as compared with the direct type backlight. Taking advantage of this advantage, this type of backlight is often mounted on liquid crystal display devices that need to be small and thin.
[0004]
However, in recent years, liquid crystal display devices have been further reduced in size, thickness, and weight, and in accordance with this, further reductions in size and thickness of backlights have been required. This reduction in size and thickness is usually achieved by reducing the size, thickness, and weight of individual components constituting the backlight, such as a light source, a light guide plate, and a housing. It is known that this can also be realized by devising. (For example, Patent Documents 1 and 2).
[0005]
FIGS. 5A and 5B show a lighting unit described in Patent Document 1, wherein FIG. 5A is a cross-sectional view and FIG. 5B is a plan view.
[0006]
The lighting unit UT includes a light source 102, a light guide plate 101 for guiding light from the light source 102, and a metal housing 104 disposed below and on the side of the light guide plate 101 and connected to the light source 102. The lead wire 103 is sandwiched between the side surface of the light guide plate 101 and the housing 104, and the lead wire 103 is held by a plurality of projections K so as not to be separated from the housing.
[0007]
[Patent Document 1]
JP-A-2001-249621 (FIG. 1 and FIG. 2 on page 3)
[Patent Document 2]
JP-A-2002-150823 (FIGS. 1, 2, and 4 on pages 5 to 6)
[0008]
[Problems to be solved by the invention]
However, in this lighting unit, the lead wire is provided with a gap between the side surface of the light guide plate and the housing, and is housed in this gap, so the housing must be enlarged by this storage space. However, as a result, the display device has also become larger.
[0009]
6A and 6B show a backlight device described in Patent Document 2, FIG. 6A is a side view, and FIG. 6B is a plan view.
The backlight device 110 includes a light guide plate 111 having a side end surface serving as an incident surface, a linear light source 112 provided in a lateral direction along the side end surface serving as a light incident surface, and a longitudinal direction of the linear light source 112. And a lead wire 113 connected to one side, and the lead wire 113 extends to the other end in the longitudinal direction of the linear light source 112. The light guide plate 111 has a rear surface that is inclined so that the plate thickness becomes thinner as the distance from the light entrance surface increases, and the light guide plate 111 is arranged such that the space below the light guide plate rear surface becomes larger as the plate thickness becomes thinner. The lead wire 113 extends through the back surface of the light guide plate 110 to the other end in the longitudinal direction of the linear light source 112 at a distance T from the light entrance surface. A part of the lead wire 113 is disposed above the lower edge of the light guide plate side end surface, which is a light incident surface, in a space below the light guide plate which becomes larger as the thickness becomes smaller.
[0010]
However, even with this wiring structure, the lead wire is wired below the lower frame with a gap T from the incident surface, so that the thickness of the display device is increased. In addition, there is a problem that if the thickness is reduced, the size of the lead wire is limited.
[0011]
An object of the present invention is to solve the problems of the above-described conventional technology, and an object of the present invention is to provide a liquid crystal display device that is reduced in size and thickness.
[0012]
[Means for Solving the Problems]
The above object is achieved by the following configurations. The liquid crystal display device of the present invention includes a substantially rectangular light guide plate having a rear surface inclined so that the plate thickness decreases from one side end to the other side end, and a plate thickness surface at one end of the light guide plate. A linear light source disposed along the light source, and lead wires respectively connected to both ends of the linear light source. The light guide plate is disposed between the rear surface of the light guide plate and the bottom wall of the housing as the plate thickness decreases. The lead wire is installed so as to be enlarged, and the lead wire is partially routed within the gap and is routed along the other end of the light guide plate, and is led out from the rear surface side of the housing. Features.
[0013]
A part of the lead wire is housed in a groove formed in the bottom wall of the housing, and is led out of the housing through the groove. A reflection plate is disposed on the back surface thereof, the reflection plate has a bent portion whose one end is bent in a substantially U-shape, and a plate thickness end of the linear light source and the light guide plate in the bent portion. Preferably, the rim is inserted.
[0014]
In this liquid crystal display device, the lead wire is wired along the other end of the light guide plate in a gap formed between the back surface of the light guide plate and the bottom wall of the housing. Therefore, the gap formed between the back surface of the light guide plate and the bottom wall of the housing can be effectively used, and the lead wire is disposed below one side edge of the light guide plate and protrudes to the outer periphery of the light guide plate or the like. Since there is no housing, the size of the housing can be reduced.
[0015]
Further, the lead wire can be prevented from moving by being housed in the groove formed in the bottom wall of the housing. Further, by assembling one end of the reflection plate into a substantially U-shape and inserting the thick edges of the linear light source and the light guide plate into the bent portion, assembly becomes easy.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 is a front view showing a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is an exploded perspective view of FIG. 1, and FIG. It is the expansion perspective view which extracted and expanded.
[0017]
The liquid crystal display device 1 includes a liquid crystal display panel 2, a lamp set 4, a light guide plate 5 for transmitting light from a light source 41 of the lamp set, and an optical member 3 arranged on a light emitting surface on the surface of the light guide plate 5. A reflection plate 6 disposed on the back surface of the light guide plate 5, a housing 7 in which an assembly of the reflection plate 6 and the like are stored, and an outer frame for surrounding the outer periphery of the housing and fixing the optical member, the liquid crystal display panel and the like. 9 and so on.
[0018]
Hereinafter, main components constituting the display device will be described with reference to the drawings. The light guide plate 5 is formed of a rectangular plate having substantially the same horizontal and vertical widths as the liquid crystal display panel 2, and is formed of an acrylic resin material or the like. As shown in the cross-sectional view of FIG. 2, the plate thickness is such that the front surface 51 is flat and the back surface 52 is gradually thinned from one side end 53 to the other side end 54 in a direction orthogonal to the longitudinal direction. And has a substantially wedge-shaped cross section. The plate thickness of the one end 53 is formed to be substantially the same as the diameter of the linear light source 41. In the light guide plate 5, one end 53 is a light incident surface, and the surface 51 is a light emitting surface.
[0019]
The optical sheet 3 is composed of a laminate of one light diffusing plate 3c and a plurality of lens sheets 3a and 3b laminated on the light diffusing plate 3c. The light diffusion plate 3c and the lens sheets 3a, 3b are formed of a non-conductive material.
[0020]
The reflecting plate 6 reflects the light entering from the light incident surface 53 of the light guide plate 5 and emits the light from the light emitting surface 51, and a reflecting material is applied to the surface thereof. The shape is such that the flat surface 61 has substantially the same size as the light guide plate 5, and one end in the longitudinal direction is bent in a U-shape to form a bent portion 62, and a gap is formed inside the bent portion 62. The linear light source 41 is housed in the bent portion 62.
[0021]
The other end 64 is bent substantially 90 ° from the flat surface 61, and a locking piece 65 for locking the one end 54 of the light guide plate 5 is formed.
[0022]
The lamp set 4 includes a linear light source 41 and lead wires 43 and 44 (hereinafter, referred to as first and second lead wires 43 and 44) connected to the linear light source. As the linear light source 41, a small-diameter fluorescent lamp such as a cold cathode or hot cathode tube is used, and is turned on by a high-frequency AC power supply. The fluorescent lamp is preferably linear, but is not limited to this, and L-shaped and U-shaped fluorescent lamps can also be used. Further, at both ends of the fluorescent lamp 41, lamp holders 42a and 42b are mounted so that the first and second lead wires 43 and 44 are led out. Each of the first and second lead wires 43 and 44 has a substantially circular or elliptical cross section, and has a diameter of about 1.0 to 1.2 mm. The lead wire is not limited to these, and a flat lead wire can be used.
[0023]
The first and second lead wires 43 and 44 are bent into a predetermined shape when housed in the housing. That is, the first lead wire 43 extends from the lamp holder 42a along the short side portion 43a along the short side of the light guide plate 5, the long side portion 43b along the long side of the light guide plate 5, and from the middle of the long side portion. And a bent portion 43c bent toward the back side. The second lead wire 44 is relatively longer than the first lead wire 43, and is drawn out of the lamp holder 42 and has a short side portion 44a along the short side of the light guide plate 5 and a long side portion along the long side. 44b, and a bent portion 44c bent from the middle of the long side portion to the back surface side. An electrical connector 45 is connected to the tips of the first and second lead wires 43 and 44. The lead wires 43 and 44 are led to the outside by being bent toward the rear surface side of the housing at the bent portions 43c and 44c.
[0024]
The housing 7 has a box shape with an open upper surface and a shallow bottom. The housing 7 has a bottom wall 70 and an outer peripheral wall 71 of a predetermined height erected from the outer periphery of the bottom wall 70 and is formed of a synthetic resin material. Is done. The outer peripheral wall 71 is composed of long side walls 71a and 71b and short side walls 71c and 71d, and the side walls are integrally connected at corners. Openings 73a, 73b are formed in the opposing side walls 71c, 71d, and these openings are provided with grounds 13a, 13b and ground terminals 63a, 63b (see FIG. 3, the ground terminal 63b is omitted in this figure). Inserted. An opening 73d is formed in the side wall 71b, and the first and second lead wires 43 and 44 are attached to the inside of the housing 7 from the opening 73d, and are led out from the back side of the housing 7.
[0025]
The bottom wall 70 has an inclined surface that matches the shape of the back surface 52 of the light guide plate 5. By providing the inclined surface, when the light guide plate 5 is placed on the inclined surface, the back surface 52 of the light guide plate 5 comes into contact with the light guide plate 5, so that the fixing of the light guide plate 5 is stabilized.
[0026]
Further, in the bottom wall 70, concave grooves 72a and 72b are formed near the inner peripheral wall surfaces of the long side walls 71a and 71b. Of these concave grooves, one concave groove 71a has a width length in which the U-shaped portion 62 of the reflection plate 6 is stored, and the other concave groove 72b has a groove width of the first and second lead wires. 43 and 44 are formed to have a width that accommodates them. Instead of the concave groove, a projecting piece (not shown) projecting from the bottom wall may be provided, and a space of a predetermined width may be formed between the projecting piece and the inner peripheral wall surface. Thin plate-like projections 72c ', 72d' are erected at a predetermined distance from the inner wall surface of the short side, and spaces 72c, 72d for accommodating the first and second lead wires 44, 43 are formed. Further, the bottom wall 70 is formed with a plurality of openings 70a to 70d of a predetermined size in a portion excluding the vicinity of the inner peripheral end.
[0027]
These parts are assembled in the following procedure. First, the lamp set 4 is set. In the set, the lamp holders 42a and 42b are attached to both ends of the fluorescent lamp 41 such that the first and second lead wires 43 and 44 are led out. Next, the first lead wire 43 extends from one end of the lamp holder 42a to the short side portion 43a along the short side of the light guide plate 5, the long side portion 43b along the long side, and the middle 43c of the long side portion to the outside. Bend to derive. The second lead wire 44 is also led out of the lamp holder 42b from a short side portion 44a along the short side of the light guide plate 5, a long side portion 44b along the long side, and a midway 44c of the long side portion. To bend. An electric connector 45 is connected to the ends of the first and second lead wires 43 and 44. The bending of the first and second lead wires 43 and 44 may be performed at the time of attachment to the housing 7.
[0028]
The lamp set 4 is set as described above, and the fluorescent lamp 41 of the unit is inserted into the U-shaped bent portion 62 of the reflector 6. Subsequently, the light guide plate 5 is inserted into the bent portion 62 from one end 53 (plate thickness side), and the other end 54 (thin thickness side) is locked to the locking piece 65 of the reflection plate 6.
[0029]
Next, the reflection plate 6 to which the light guide plate 5 is attached is mounted on the housing 7. First, the reflector 6 is inclined obliquely so that the bent portion 62 is fitted into the concave groove 72a, and the lamp holders 42a and 42b of the fluorescent lamp 41 are also fitted and fixed in the groove 72a. Next, the bent portions 43a and 43b of the first lead wire 43 are packed in the space 72d and the concave groove 72b. In the vicinity of the opening 73d, an opening is also formed on the bottom surface of the concave groove. Therefore, the lead wire 43 is arranged at the opening of the concave groove 72b through the opening 73d, and is led out from the rear surface side of the housing 7. The bent portions 44a and 44b of the second lead wire 44 are also packed in the space 72c and the concave groove 72b, arranged in the opening on the bottom surface of the concave groove 72b through the opening 73c, and led out from the back side of the housing 7. Then, the reflecting plate 6 is tilted from the oblique state, and the locking piece 65 of the reflecting plate is pressed against the inner wall surface of the long side wall 71b, and the reflecting plate 6 is stored in the housing 7. At this time, the terminals 63a and 63b of the reflection plate 6 are inserted into the openings 73a and 73b of the housing 7.
[0030]
Then, between the bottom surface of the back surface 52 and the housing 7 of the reflector 6, a gap L ₂ is formed, first, second leads 43 and 44 is disposed in the most open part of the gap Will be. In addition, since the concave groove 72b is covered by the inner lower surface of the other end 65 of the reflector 6, the lead wires 43 and 44 are pressed by the lower surface of the reflector 6 and do not jump out of the concave groove 72b. . Furthermore, the first, second lead 43 is positioned directly below substantially the other end 54 of the light guide plate 5, falls within the width L ₁ of the housing 7, the width can be narrowed. Further, since the lead wire is disposed at the maximum width of the gap, the thickness of the lead wire can be selected according to the maximum width.
[0031]
Thereafter, the optical member 3 and the liquid crystal display panel 2 are placed on the front surface 51 of the light guide plate 5, the circuit board connected to the liquid crystal display panel 2 is arranged on the back surface of the housing 7, and the periphery of these assemblies is framed. The liquid crystal display device is completed by being surrounded and fixed by the body 9 and attaching a back cover to the bottom surface.
[0032]
【The invention's effect】
According to this liquid crystal display device, the gap formed between the back surface of the light guide plate and the bottom wall of the housing can be effectively used, and the lead wire is disposed below one side edge of the light guide plate, And so on, so that the housing can be made smaller. In particular, since the lead wire is led out to the rear surface side of the housing, the shape of the side surface portion of the housing is simplified, and the housing can be further miniaturized.
[0033]
Further, the lead wire can be prevented from moving by being housed in the groove formed in the bottom wall of the housing. Further, by assembling one end of the reflection plate into a substantially U-shape and inserting the thick edges of the linear light source and the light guide plate into the U-shaped opening, assembly becomes easy.
[Brief description of the drawings]
FIG. 1 is a front view of a liquid crystal display device according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is an exploded perspective view of FIG.
FIG. 4 is an enlarged perspective view in which a part of FIG. 3 is extracted and enlarged.
5A and 5B show a conventional lighting unit, wherein FIG. 5A is a sectional view and FIG. 5B is a plan view.
6A and 6B show a conventional backlight device, wherein FIG. 6A is a side view and FIG. 6B is a plan view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal display panel 3 Optical member 4 Lamp set 41 Linear light sources 43 and 44 Lead wire 5 Light guide plate 6 Reflector 7 Housing 72a, 72b Groove

Claims (3)

A substantially rectangular light guide plate having a back surface inclined so that the plate thickness becomes thinner from one side end to the other side end, and a linear shape arranged along the plate thickness surface of one side end of the light guide plate A light source; and lead wires respectively connected to both ends of the linear light source. The light guide plate is installed such that a gap between a rear surface of the light guide plate and a bottom wall of the housing increases as the plate thickness decreases. The liquid crystal display device is characterized in that a part of the lead wire is located in the gap, is wired along the other end of the light guide plate, and is led out from the back side of the housing. 2. The liquid crystal display device according to claim 1, wherein a part of the lead wire is housed in a groove formed in a bottom wall of the housing, and is led out of the housing through the groove. . The light guide plate has a reflection plate disposed on the back surface thereof, the reflection plate has a bent portion having one end bent substantially in a U-shape, and the linear light source and the light guide plate are provided in the bent portion. The liquid crystal display device according to claim 1, wherein the edge having the thickness is inserted.

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