KR102401834B1 - Backlight unit and liquid crystal display device comprising the same - Google Patents

Abstract

An object of the present invention is to provide a backlight unit having improved light efficiency and adhesive properties by using an optically transparent adhesive between a light guide plate and a light emitting diode package, and a liquid crystal display including the same. To this end, the backlight unit includes a light emitting diode package including a bottom, a first side, a second side, and a light emitting diode chip seated on the bottom, a printed circuit board to which the light emitting diode package is connected, light is incident and an optically transparent adhesive provided between the light guide plate and the light emitting diode package, and the optically transparent adhesive may be provided in a space between the first side and the second side.

Description

Backlight unit and liquid crystal display including same

The present invention relates to a backlight unit and a liquid crystal display including the same.

A general liquid crystal display displays an image by using a thin film transistor as a switching element. Such a liquid crystal display device is widely used as a display device for a notebook computer, a tablet computer, a smart phone, a portable display device, a portable information device, etc. in addition to a display device for a television or a monitor. Since such a liquid crystal display is not a self-luminous method, an image is displayed using light irradiated from a backlight unit disposed under the liquid crystal display panel.

Recently, a backlight unit using a light emitting diode (LED), which has a long lifespan, low power consumption, and can be miniaturized, has been developed as a light source, and such a backlight unit is being applied from a small liquid crystal display to a large liquid crystal display.

The backlight unit is divided into a direct type and an edge type according to the arrangement position of the light source. Recently, the edge type backlight unit has been widely applied to slim the liquid crystal display device.

1 is a cross-sectional view schematically illustrating a general edge-type backlight unit. FIG. 2 is a cross-sectional view of the package of the light emitting diode shown in FIG. 1, and FIG. 3 is a view showing the problems according to the prior art.

1 and 2 , a typical edge type backlight unit includes a printed circuit board 1 , a light emitting diode package 2 , a light emitting diode chip 3 , and a light guide plate 4 .

The printed circuit board 1 is disposed on one side of the light guide plate 4 to face the light incident surface of the light guide plate 4 . The light emitting printed circuit board 1 includes a plurality of light emitting diode packages 2 arranged at regular intervals.

The light emitting diode package 2 includes a light emitting diode chip 3 , a first terminal 5 , a second terminal 6 , and an encapsulation layer 7 . In this conventional light emitting diode package, first color light is emitted by light emission of the light emitting diode chip 3 according to the driving power applied to the first and second terminals 5 and 6 , and the light emitting diode chip 3 . Some of the first color light emitted by the primary light emission is converted to the second color light by light absorption by the phosphor mixed in the encapsulation layer 7 and the secondary light emission to the light exit surface of the encapsulation layer 7 . is emitted, and the remainder of the first color light is scattered by the phosphor and emitted to the light exit surface. Accordingly, the conventional light emitting diode package emits white light by mixing the first color light and the second color light.

The light guide plate 4 internally refracts and reflects the light incident from the light emitting diode package 2 through a planar light incident surface provided on one side to emit it in the upper surface direction.

As shown in FIG. 1 , in such a general edge type backlight unit, an air gap exists between the light emitting diode package 2 and the light guide plate 4 . For this reason, as can be seen in FIG. 3 , in the related art, when light emitted from the light source of the light emitting diode package 2 comes out into the air through the encapsulation layer 7 , total reflection occurs due to a difference in refractive index between the encapsulation layer 7 and the air. . As a result, some light is not emitted to the outside or is scattered, and thus overall light efficiency and luminance of the backlight unit may be deteriorated.

The present invention has been devised to solve the above problems, and a backlight unit capable of increasing the light efficiency of the backlight unit by reducing light loss by providing an optically transparent adhesive between the light incident surface of the light guide plate and the light emitting diode package, and a liquid crystal display device using the same It is a technical task to provide

In addition, it is another technical task to provide a backlight unit capable of improving adhesive properties and enhancing reliability of the backlight unit by providing an optically transparent adhesive between the light incident surface of the light guide plate and the light emitting diode package, and a liquid crystal display device using the same. .

A backlight unit according to the present invention for achieving the above technical problem includes a light emitting diode package having a bottom, a first side, a second side, and a light emitting diode chip seated on the bottom, the light emitting diode package A printed circuit board connected thereto, a light guide plate having a light incident surface on which light is incident, and an optically transparent adhesive provided between the light guide plate and the light emitting diode package, wherein the optically transparent adhesive may be provided in a space between the first side and the second side have.

According to the means for solving the above problems, the present invention has the following effects.

First, the adhesive property between the light emitting diode package and the light guide plate may be improved, so that the reliability of the backlight unit may be improved.

Second, an air gap between the light emitting diode package and the light guide plate is removed, so that the light efficiency of the backlight unit may be improved.

Third, the process can be simplified by deleting and integrating the existing light emitting diode package manufacturing process.

In addition to the effects of the present invention mentioned above, other features and advantages of the present invention will be described below or will be clearly understood by those of ordinary skill in the art from such description and description.

1 is a cross-sectional view showing a conventional backlight unit;
2 is a cross-sectional view showing a conventional light emitting diode package;
3 is a diagram illustrating a problem of a conventional backlight unit;
4 is a view showing a backlight unit according to the present invention;
5 is a cross-sectional view illustrating a light emitting diode package according to the present invention.
6 is a diagram illustrating a backlight unit according to a second embodiment of the present invention.
7 is a diagram illustrating a backlight unit according to a third embodiment of the present invention.
8 is a diagram illustrating a backlight unit according to a fourth embodiment of the present invention.
9 is a diagram illustrating a backlight unit according to a fifth embodiment of the present invention.
10 is a diagram illustrating a backlight unit according to a sixth embodiment of the present invention.
11 is a diagram illustrating a state in which light leakage occurs in a light incident part because a condition of total internal reflection is not satisfied.
12 is a diagram illustrating a backlight unit according to a seventh exemplary embodiment of the present invention.
13 is a diagram illustrating a backlight unit according to an eighth embodiment of the present invention.
14 is a diagram illustrating a liquid crystal display including a backlight unit according to the present invention.

The meaning of the terms described in this specification should be understood as follows.

The singular expression is to be understood as including the plural expression unless the context clearly defines otherwise, and the terms "first", "second", etc. are used to distinguish one element from another, The scope of rights should not be limited by these terms. It should be understood that terms such as “comprise” or “have” do not preclude the possibility of addition or existence of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. The term “at least one” should be understood to include all possible combinations of one or more related items. For example, the meaning of “at least one of the first, second, and third items” means that each of the first, second, or third items as well as two of the first, second and third items It means a combination of all items that can be presented from more than one. The term “on” is meant to include not only cases in which a certain component is formed directly above another component, but also a case in which a third component is interposed between these components.

Hereinafter, preferred examples of a backlight unit and a liquid crystal display having improved adhesion properties between the light emitting diode package and the light guide plate according to the present invention will be described in detail with reference to the accompanying drawings.

In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

4 is a view showing a backlight unit according to the present invention, and FIG. 5 is a view showing a light emitting diode package according to the present invention.

4 and 5 , the backlight unit according to the present invention includes a printed circuit board 50 , a light emitting diode package 100 , a light guide plate 200 , and an optically transparent adhesive 300 .

The printed circuit board 50 is disposed on one side of the light guide plate 200 to face the light incident surface 201 of the light guide plate 220 . The printed circuit board 50 includes an anode power line for supplying anode power to the anode terminal of each of the plurality of light emitting diode packages 100 and a cathode power supply to the cathode terminal of each of the plurality of light emitting diode packages 100. Includes a cathode power line.

Each of the light emitting diode packages 100 is mounted on the printed circuit board 50 at regular intervals and irradiates light to the light incident part 201 of the light guide plate 200 . The light emitting diode package 100 includes a bottom portion 101 , a first side portion 102 , a second side portion 103 , and a light emitting diode chip 110 . The bottom portion 101 , the first side portion 102 , and the second side portion 103 may be made of a high heat dissipation material such as metal, for example, a material such as aluminum (Al). Due to this, heat dissipation of the light emitting diode package 100 may increase, and thus the lifespan and reliability of the light emitting diode package 100 may increase.

The bottom portion 101 means a portion in contact with the light emitting diode package 100 and the printed circuit board 50 . The upper surface of the bottom 101 supports the light emitting diode chip 110 . In this case, the bottom 101 is made of metal and can serve as an electrode at the same time.

The first and second side portions 102 and 103 may be inclined by an obtuse angle from the top surface of the bottom portion 101 to have a wider surface from the top to the bottom. The first and second sides 102 and 103 define a light emitting space of the light emitting diode package 100 . That is, the inclined inner surfaces of the first and second sides 102 and 103 reflect the light generated by the light emitting diode chip 110 , so that the light is emitted to the upper portion of the light emitting diode package 100 . Here, the first side 101 protrudes from the bottom 101 and surrounds one side of the light emitting diode chip 110 , and the second side 102 protrudes from the bottom 101 of the light emitting diode chip 110 . surround the other side.

The light emitting diode chip 110 is disposed on the bottom 101 of the light emitting diode package 100 and is electrically connected to the bottom 101 . The light emitting diode chip 110 emits excitation light, that is, first color light according to the supplied driving power. For example, the light emitting diode chip 110 may be a blue light emitting diode chip emitting blue light or a white bladder diode chip emitting white light.

On the other hand, the light emitting diode chip 110 according to an example of the present invention has a flip chip structure applied, but this is not necessarily the case, and a lateral chip or vertical chip structure may be applied. have.

The light emitting diode chip 110 includes a first terminal 111 provided on one side of the light emitting diode chip 110 , a second terminal 112 provided on the other side, and a body portion 115 .

The first terminal 111 and the second terminal 112 are electrically connected to a lead electrode (not shown) provided on the bottom 101 of the light emitting diode package 100 . The main body 115 may include a light emitting diode substrate, a buffer layer, first and second semiconductor layers, an active layer, and a reflective layer.

The light emitting diode substrate may be made of a material such as sapphire (Al2O3), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), or gallium arsenide (GaAs). Here, sapphire is mainly used as a substrate for a blue or green light emitting device because it is relatively easy to grow a GaN-based semiconductor material and is stable at a high temperature.

The buffer layer is formed between the substrate and the first semiconductor layer in order to reduce a lattice constant difference between the substrate and the first semiconductor layer, and may be made of a material of GaN or AlN.

The first semiconductor layer is formed on the buffer layer to provide electrons to the active layer. The first semiconductor layer according to an example may be made of an n-GaN-based semiconductor material, and the n-GaN-based semiconductor material may be GaN, AlGaN, InGaN, AlInGaN, or the like.

The active layer is formed on the first semiconductor layer to emit light. The active layer has a multi-quantum well (MQW) structure with a high band gap. In addition, the second semiconductor layer is formed on the active layer to provide holes to the active layer.

The light guide plate 200 has a rectangular plate shape to include a light incident surface 201 provided on at least one side thereof. The light guide plate 200 includes an optical pattern (not shown) for emitting the light incident from the light incident part 201 in the upper surface direction.

The optically clear adhesive 300 , OCR, and Optical Clear Resin is provided between the light emitting diode package 100 and the light guide plate 200 . The optically transparent adhesive 300 is made of a resin having excellent adhesion having transparency, and improves visibility of the display and reduces blurring in a bright external environment (ie, under sunlight). The optically transparent adhesive 300 can thin the liquid crystal display panel by filling the existing air gap with an optically transparent resin, and thus high visibility and high contrast can be obtained.

If there is an air gap between the light emitting diode package 100 and the light guide plate 200 , the light to be transmitted is reflected or scattered due to the difference in the refractive index of each medium, resulting in light loss. That is, when the light emitted from the light emitting diode package 100 meets air, all of the light above a certain angle is reflected at the interface due to a difference in refractive index, resulting in light loss. Therefore, when the air gap is removed by filling the optically transparent adhesive 300 according to the present invention between the light emitting diode package 100 and the light guide plate 200 , light loss due to total internal reflection can be prevented and light efficiency can be improved. In addition, by filling the optically transparent adhesive 300 , adhesive properties between the light emitting diode package 100 and the light guide plate 200 are improved, thereby improving the reliability of the backlight unit.

Additionally, as can be seen in FIG. 4 , the optically clear adhesive 300 is also filled in a space defined inwardly between the first and second sides 102 and 103 of the light emitting diode package 100 . That is, in the prior art, the space defined between the first and second sides 102 and 103 of the light emitting diode package 100 is filled with an encapsulation layer to encapsulate the light emitting diode chip 110, but the light emitting diode according to the present invention In the package 100 , the optically transparent adhesive 300 is filled between the first and second sides 102 and 103 of the diode package 100 , and serves to encapsulate the light emitting diode chip 110 .

For this reason, the process of forming the encapsulation layer encapsulating the light emitting diode chip 110 can be eliminated by applying and curing the encapsulation material, thereby simplifying the process. In addition, since the optically transparent adhesive 300 is filled inside the light emitting diode package 100 , the bonding area is widened, and thus the reliability of the backlight unit related to the bonding area can be improved.

In addition, as can be seen in FIG. 4 , the optically transparent adhesive 300 is disposed between the outer surface of the first side 101 and the second side 102 of the light emitting diode package 100 and the printed circuit board 50 . The defined space is also filled. As described above, by bonding to the printed circuit board as well as the light emitting diode package 100 , the bonding area is maximized, and thus the reliability of the backlight unit related to the contact characteristic may be improved.

6 is a cross-sectional view illustrating a backlight unit according to a second embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

6 , the backlight unit according to the second embodiment of the present invention may include an air gap 350 between the printed circuit board 50 and the optically transparent adhesive 300 . The air gap 350 may have a rectangular space including one side 350a, the other side 350b facing the one side 350a, and a height 350c.

One side 350a means the distance from the upper end of the first side 101 of one light emitting diode package 100 to the upper end of the second side 102 of the other light emitting diode package 100, and facing the one side The other side 350b means from the lower end of the first side 101 of one light emitting diode package 100 to the lower end of the second side 102 of the other light emitting diode package 100 . The height 350c refers to a distance from the printed circuit board 50 to the point where the first and second sides 101 and 102 of the light emitting diode package 100 meet the optically clear adhesive 300 .

The backlight unit according to the second embodiment of the present invention including the air gap 350 maintains the same level of adhesion and light efficiency as those of the first embodiment, but due to the space occupied by the air gap 350 , There is an advantage in that the amount of filling of the optically transparent adhesive 300 can be reduced.

7 is a cross-sectional view illustrating a backlight unit according to a third exemplary embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 7 , the backlight unit according to the third embodiment of the present invention may further include a fluorescent material 450 in addition to the optically transparent adhesive 300 .

In a backlight unit for a liquid crystal display, the light emitting diode chip 110 is generally formed of a blue light emitting diode chip emitting blue light or a white light emitting diode chip emitting white light. In the case of a blue light emitting diode chip, it is converted back into white light through a color filter or other optical sheets. The backlight unit according to the present invention may include a blue light emitting diode chip emitting blue light or a white bladder diode chip emitting white light.

The fluorescent material may be a yellow fluorescent material, but is not limited thereto, and may be one or more color fluorescent materials for generating white light according to the color light emitted from the light emitting diode chip 110 . It is assumed that it is a yellow fluorescent material. The yellow fluorescent material absorbs a portion of the blue light emitted from the light emitting diode chip 110 to emit yellow light. Accordingly, in the optically transparent adhesive 300 , white light is generated by mixing the blue light emitted from the light emitting diode chip 110 and the yellow light emitted by the fluorescent material to be emitted to the outside.

As described above, the optically transparent adhesive 300 including the fluorescent material 450 according to the second embodiment of the present invention may include an optical sheet for converting into white light while increasing light efficiency using a blue light emitting diode chip. no need. Therefore, there is an advantage in that the slim of the liquid crystal display can be achieved due to the removal of the optical sheet.

In addition, the optically transparent adhesive 300 according to the present invention may be filled between the light emitting diode package 100 and the light guide plate 200 to minimize an air gap, thereby preventing light loss due to a difference in refractive index. In addition, by filling the optically transparent adhesive 300 , adhesive properties between the light emitting diode package 100 and the light guide plate 200 are improved, thereby improving the reliability of the backlight unit.

8 is a cross-sectional view illustrating a backlight unit according to a fourth embodiment of the present invention. A duplicate description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 8 , in the backlight unit according to the fourth embodiment of the present invention, an optically transparent film 400 , OCA, Optical having excellent light transmittance is additionally provided between the optically transparent adhesive 300 and the light incident surface 201 of the light guide plate 200 . Clear Adhesive) may be further included.

In general, the optically transparent film 400 is adhered between the light emitting diode package 100 and the light incident surface 201 of the light guide plate 200 to eliminate the air gap. However, in this case, there is often a fine empty space on the bonding surface, which may cause a defect in the reliability test after bonding.

Accordingly, in the fourth embodiment of the present invention, the optically transparent film 400 is provided to face the light incident surface 201 of the light guide plate 200 by adhering it to the optically transparent adhesive 300 and the upper surface. When the optically transparent film 400 is adhered to the upper surface of the optically transparent adhesive 300 made of a resin, the adhesive property is higher than when the optically transparent film 400 is adhered alone to the upper surface of the light emitting diode package 100 as in the prior art. improved to improve the reliability of the backlight unit.

In addition, the optically transparent adhesive 300 according to the present invention may be filled between the light emitting diode package 100 and the light guide plate 200 to minimize an air gap, thereby preventing light loss due to a difference in refractive index.

9 is a cross-sectional view illustrating a backlight unit according to a fifth embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 9 , the backlight unit according to the fifth embodiment of the present invention may further include a protrusion 210 on the light incident surface 201 of the light guide plate 200 .

The protrusion 210 is provided in a region that does not overlap the light emitting diode package 100 . That is, the protrusion 210 of the light guide plate 200 is disposed in a space corresponding to a region between one light emitting diode package 100 and the other light emitting diode package 100 . Although it is illustrated that the protrusion 210 does not descend to the first and second sides 102 and 103 of the light emitting diode package 100 in the drawing, the present invention is not limited thereto.

If the protrusion 210 descends to the top of the first and second side portions 102 and 103 of the light emitting diode package 100 , the light incident surface 201 of the light guide plate 200 is a region that does not overlap the light emitting diode package 100 . and the protrusion 210 , which may be advantageous in terms of alignment during the bonding process.

As described above, in the backlight unit having the light guide plate 200 including the protrusion 210 according to the fifth embodiment of the present invention, the optically clear adhesive 300 is applied to the space between the protrusion 210 and the other protrusion 210 . By filling, adhesion properties between the light emitting diode package 100 and the light guide plate 200 are further improved, thereby improving the reliability of the backlight unit.

In addition, the optically transparent adhesive 300 according to the present invention may be filled between the light emitting diode package 100 and the light guide plate 200 to minimize an air gap, thereby preventing light loss due to a difference in refractive index. Additionally, it is possible to reduce the amount of filling of the optically transparent adhesive 300 as much as the area corresponding to the protrusion 210 .

10 is a cross-sectional view illustrating a backlight unit according to a sixth embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 10 , in the case of the backlight unit according to the sixth embodiment of the present invention, the light incident surface 201 of the light guide plate 200 has a rougher surface than the other three surfaces. That is, in the backlight unit according to the sixth embodiment of the present invention, a roughness characteristic is imparted to the light incident surface 201 on which the light emitted from the light emitting diode package 100 is incident among the four surfaces of the light guide plate 200 .

The figure shown at the bottom of FIG. 10 is an enlarged view of the surface of the light guide plate 200 having the rough light incident surface 201 .

If the light incident surface 201 of the light guide plate 200 according to the sixth embodiment of the present invention has a rough surface, the adhesion area with the optical adhesive film 300 may be increased due to the curved area of the surface. . Accordingly, the surface adhesion property of the light-receiving surface 201 of the light guide plate 200 is improved compared to the case where the light-receiving surface 201 has a smooth mirror surface, thereby improving the reliability of the backlight unit. In addition, the optically transparent adhesive 300 according to the present invention may be filled between the light emitting diode package 100 and the light guide plate 200 to minimize an air gap, thereby preventing light loss due to a difference in refractive index.

11 is a diagram illustrating a state in which light leakage occurs in a light incident part because a condition of total internal reflection is not satisfied. 12 is a diagram illustrating a backlight unit according to a seventh exemplary embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 11 , light leakage (region A) may occur at both edges of the light incident surface 201 in contact with the optically transparent adhesive 300 , as the condition for total internal reflection is not satisfied. That is, a portion of the light emitted from the light emitting diode chip 110 does not pass through the light incident surface 201 on the light guide plate 200 and is reflected, so that light efficiency may be reduced.

Therefore, in order to improve the above problems, as shown in FIG. 12 , the optically transparent adhesive 300 of the backlight unit according to the seventh embodiment of the present invention may have a structure in which both sides have a chamfer shape. That is, both side edges of the light incident surface 201 in contact with the light guide plate 200 may be cut to have a cross-sectional shape at a predetermined angle.

That is, the optically transparent adhesive 300 according to the seventh embodiment includes a first surface 301 in contact with the light incident surface 201 of the light guide plate 200 , a second surface 302 in contact with the light emitting diode package 100 , and the second surface 302 in contact with the light emitting diode package 100 . It has a third side 303 and a fourth side 304 connecting the first side 301 and the second side 302 , and the length of the first side 301 is greater than the length of the second side 302 . It has a long trapezoidal structure. As described above, the backlight unit according to the seventh embodiment of the present invention can prevent light loss due to total internal reflection as well as the effect of improving adhesive properties as described above. Here, the chamfer angle θ1 of the optically transparent adhesive 300 may be from 45 degrees to 75 degrees, and preferably, when the angle of 75 degrees is achieved, light leakage may be minimized.

13 is a cross-sectional view illustrating a backlight unit according to an eighth embodiment of the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

Referring to FIG. 13 , the backlight unit according to the eighth embodiment of the present invention may include the optically transparent adhesive 300 according to the seventh embodiment and additionally a light guide plate 200 having a chamfer shape. That is, the optically transparent adhesive 300 according to the eighth embodiment includes a first surface 301 in contact with the light incident surface 201 of the light guide plate 200 , a second surface 302 in contact with the light emitting diode package 100 , and the second surface 302 in contact with the light emitting diode package 100 . It has a third side 303 and a fourth side 304 connecting the first side 301 and the second side 302 , and the length of the first side 301 is greater than the length of the second side 302 . It has a long trapezoidal structure. Additionally, both edges of the light incident surface of the light guide plate 200 may also be cut to have a cross-sectional shape at a predetermined angle.

In the case of the backlight unit according to the eighth embodiment of the present invention, an optimal chamfer shape can be implemented in addition to the chamfer shape having a predetermined angle θ2 on both edges of the light incident surface 201 of the light guide plate 200 . That is, the third side 303 and the fourth side 304 of the optically transparent adhesive 300 are provided in a chamfer shape having an angle θ2 of 45 degrees to 75 degrees, and additionally the light incident surface 201 of the light guide plate 200 . ) In addition, when the optically transparent adhesive 300 has a chamfered shape, it is possible to control an optical path that can improve light leakage due to total internal reflection, rather than when only the optically transparent adhesive 300 has a chamfered shape.

As such, in the case of the backlight unit according to the eighth embodiment of the present invention, there are various advantages of improving light efficiency due to removal of an air gap, improving adhesion properties due to the optically transparent adhesive 300 and preventing light leakage.

14 is a cross-sectional view schematically illustrating a liquid crystal display including a backlight unit according to the present invention. The overlapping description of the same components as those of the light emitting diode package 100 , the light guide plate 200 and the optically transparent adhesive 300 described above in FIGS. 4 and 5 will be omitted.

The liquid crystal display according to the present invention includes a reflective sheet 500 , a rear cover 600 , an optical sheet 700 , and a liquid crystal panel 800 .

The reflective sheet 500 is disposed on the lower surface of the light guide plate 200 and is accommodated in the rear cover 600 . The reflective sheet 500 reflects light incident from the light guide plate 200 toward the light guide plate 200 , thereby minimizing loss of light traveling toward the rear surface of the light guide plate 200 .

The rear cover 600 accommodates the backlight unit and supports the guide frame. The rear cover 600 according to an example includes a cover plate that covers the rear surface of the backlight unit while supporting the backlight unit, and a sidewall of the cover bent from an edge portion of the cover plate to provide an accommodation space on the cover plate.

The optical sheet unit 700 is disposed on the light guide plate 200 and may include, but is not limited to, a lower diffusion sheet, a prism sheet, and an upper diffusion sheet, and a diffusion sheet, a prism sheet, and dual brightness enhancement. Film (dual brightness en-hancement film), and may be made of a laminated combination of two or more selected from the lenticular sheet.

The liquid crystal display panel 800 displays an image using light passing through a liquid crystal layer, and includes a lower substrate 803 , an upper substrate 802 , a lower polarizing member 804 , and an upper polarizing member 801 . may include

The lower substrate 803 is a thin film transistor array substrate, and includes a pixel array including a plurality of pixels (not shown) formed in each pixel area intersected by a plurality of gate lines (not shown) and a plurality of data lines (not shown). include Each pixel may include a thin film transistor (not shown) connected to a gate line and a data line, a pixel electrode connected to the film transistor, and a common electrode formed adjacent to the pixel electrode and supplied with a common voltage.

The upper substrate 802 includes a pixel defining pattern defining an opening region overlapping each pixel region formed on the lower substrate 803 and a color filter formed in the opening region. The upper substrate 802 is oppositely bonded to the lower substrate 803 with a liquid crystal layer (not shown) interposed therebetween by a sealant to cover the entire lower substrate 803 .

At least one of the lower substrate 803 and the upper substrate 802 is formed with an alignment layer (not shown) for setting a pretilt angle of the liquid crystal. The liquid crystal layer is interposed between the lower substrate 803 and the upper substrate 802, and liquid crystal molecules are arranged in a horizontal direction according to a transverse electric field formed by a data voltage and a common voltage applied to the pixel electrode for each pixel. is made of

The lower polarization member 804 is attached to the lower surface of the lower substrate 803 , polarizes the light incident from the light source module 120 along the first polarization axis, and irradiates the light onto the lower substrate 803 .

The upper polarizing member 801 is attached to the upper surface of the upper substrate 802 to polarize light emitted to the outside through the upper substrate 802 .

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical matters of the present invention. It will be clear to those who have the knowledge of Therefore, the scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

50: printed circuit board 100: light emitting diode package
110: light emitting diode chip 200: light guide plate
300: optical adhesive adhesive 350: air gap
400: optical adhesive film 450: fluorescent material
500: reflective sheet 600: rear case
700 optical sheet 800 liquid crystal panel

Claims (14)

bottom,
a light emitting diode package including a first side extending from one end of the bottom part, a second side extending from the other end of the bottom part, and a light emitting diode chip mounted on the bottom part;
a printed circuit board to which the light emitting diode package is connected;
a light guide plate having a light incident surface on which light is incident; and
An optically transparent adhesive provided between the light guide plate and the light emitting diode package,
The optically clear adhesive fills a space between the first side and the second side, and is in direct contact with the inner surface of the first side, the inner surface of the second side and the inner surface of the bottom. delete The method of claim 1,
A backlight unit in which the optically clear adhesive further contacts an outer surface of the first side and an outer surface of the second side. 4. The method of claim 3,
A backlight unit in which the optically transparent adhesive is further in contact with the upper surface of the light emitting diode printed circuit board. 4. The method of claim 3,
A backlight unit having an air gap between the optically transparent adhesive and a top surface of the light emitting diode printed circuit board. The method of claim 1,
The backlight unit further comprising an optically transparent film between the light incident surface of the light guide plate and the optically transparent adhesive. The method of claim 1,
The optically transparent adhesive further comprises a fluorescent material, the backlight unit. The method of claim 1,
The light guide plate has four surfaces including the light incident surface,
and a roughness of the light incident surface of the light guide plate is coarser than that of the remaining three surfaces of the light guide plate. The method of claim 1,
The light guide plate further includes a protrusion on a light incident surface. 10. The method of claim 9,
The protrusion is provided in a region that does not overlap the light emitting diode package, the backlight unit. delete a light emitting diode package having a bottom, a first side extending from one end of the bottom, a second side extending from the other end of the bottom, and a light emitting diode chip seated on the bottom;
a printed circuit board to which the light emitting diode package is connected;
a light guide plate having a light incident surface on which light is incident; and
an optically transparent adhesive disposed between the light incident surface of the light guide plate and the light emitting diode package, and in direct contact with the first side, the second side and the bottom of the light emitting diode package and the light incident surface of the light guide plate do,
The optically transparent adhesive is
a first surface in direct contact with the light incident surface of the light guide plate;
a second surface in direct contact with the bottom of the light emitting diode package;
and a third side and a fourth side connecting the first side and the second side,
The length of the first surface is longer than the length of the second surface,
The third side and the fourth side are inclined toward the second side, the backlight unit. rear case with storage space;
a reflective plate covering the storage space;
a plurality of optical sheets provided on the light guide plate;
a liquid crystal panel disposed on the optical sheet; and
A liquid crystal display device further comprising the backlight unit according to claim 1 or 12 . 13. The method of claim 12,
Both edges of the light-receiving surface in contact with the optically transparent adhesive have a chamfer shape, the backlight unit.

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