KR20080030778A - Back light assembly and liquid crystal display apparatus having the same - Google Patents

Abstract

A backlight assembly and an LCD(Liquid Crystal Display) having the backlight assembly are provided to arrange only a single diffusion sheet on a light guide plate having prism patterns formed on the bottom face and the top face thereof so as to reduce the cost, thickness and weight of the backlight assembly. A backlight assembly(100) includes a lamp(110), a light guide plate(200), a reflecting sheet(120) and at least one optical sheet(130). The light guide plate includes a light-receiving face, a bottom face having a first prism pattern(250) including first prisms formed at a predetermined interval and flat portions formed between neighboring first prisms and a top face having a second neighboring prism pattern(270). The flat portions are perpendicular to the light-receiving face. The first prism pattern has a stripe shape formed in parallel with the light-receiving face. The reflecting sheet is located under the light guide plate. The optical sheet is arranged on the light guide plate.

Description

BACK LIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY APPARATUS HAVING THE SAME}

1 is an exploded perspective view showing a backlight assembly according to an embodiment of the present invention.

FIG. 2 is a combined cross-sectional view of the backlight assembly shown in FIG. 1.

3 is an enlarged view illustrating in detail the first prism pattern illustrated in FIG. 2.

FIG. 4 is an enlarged view illustrating another embodiment of the first prism pattern shown in FIG. 2.

FIG. 5 is an enlarged view illustrating still another embodiment of the first prism pattern illustrated in FIG. 2.

FIG. 6 is an enlarged view illustrating still another embodiment of the first prism pattern illustrated in FIG. 2.

FIG. 7 is an enlarged view illustrating a portion of the light guide plate illustrated in FIG. 1.

8 is an exploded perspective view illustrating a backlight assembly according to another embodiment of the present invention.

9 is an exploded perspective view illustrating a backlight assembly according to another embodiment of the present invention.

10 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: backlight assembly 110: lamp

120: reflective sheet 130: optical sheet

131: diffusion sheet 132: prism sheet

134: protective sheet 200: light guide plate

250: first prism pattern 270: second prism pattern

600: liquid crystal display device 700: display unit

710: liquid crystal display panel 720: driving circuit portion

The present invention relates to a backlight assembly and a liquid crystal display device having the same, and more particularly, to a backlight assembly and a liquid crystal display device having the same, which can increase luminance and reduce manufacturing costs.

The liquid crystal display is a flat panel display that displays an image using liquid crystal, and is thinner and lighter than other display devices such as CRT and PDP, and has an advantage of low driving voltage and low power consumption. It is widely used throughout the industry.

Since a liquid crystal display device is a non-light emitting device that does not emit light by a liquid crystal display panel displaying an image, it requires a backlight assembly for supplying light to the liquid crystal display panel.

In general, the backlight assembly includes a lamp for generating light, a light guide plate (LGP) for guiding light supplied from the lamp toward the liquid crystal display panel, and a reflective sheet disposed under the light guide plate.

However, the backlight assembly uses a plurality of optical sheets such as a diffusion sheet, a prism sheet, and a protective sheet to improve the brightness and uniformity of the light emitted from the light guide plate, thereby increasing the manufacturing cost and increasing the thickness of the product. Is generated.

Accordingly, the present invention has been made in view of such a problem, and the present invention provides a backlight assembly capable of reducing manufacturing costs while improving luminance.

In addition, the present invention provides a liquid crystal display device having the above-described backlight assembly.

According to an aspect of the present invention, a backlight assembly includes a lamp for generating light, a light guide plate, a reflective sheet disposed below the light guide plate, and at least one optical sheet disposed above the light guide plate. The light guide plate includes an incidence plane to which light from the lamp is incident, a first prism pattern formed to be spaced apart from each other, and a lower surface including a flat portion formed perpendicular to the incidence plane between the first prism patterns, and a first contacting part connected to each other. It includes an upper surface on which two prism patterns are formed. The light guide plate is reduced in thickness away from the incident surface. The first prism patterns have a stripe shape formed in parallel with the incident surface.

The first prism pattern extends in parallel with the first inclined surface from the first inclined surface formed to be inclined in the upper surface direction from the flat part, the second inclined surface inclined in the lower surface direction from the first inclined surface, and the first inclined surface. It includes a third inclined surface connected to the flat portion. The first inclined surface and the second inclined surface may have a substantially symmetrical or asymmetrical structure with respect to the normal of the flat portion.

The second prism patterns have a stripe shape formed in a direction perpendicular to the first prism patterns. The vertex angle of the second prism pattern may be formed at 80 degrees to 150 degrees.

In an embodiment, the optical sheet may include a prism sheet having third prism patterns connected to each other on an upper surface thereof. The third prism patterns may have a stripe shape formed in a direction parallel to or perpendicular to the second prism patterns. In this case, a vertex angle of the third prism pattern may be formed at 80 degrees to 150 degrees. The optical sheet may further include a protective sheet disposed on the prism sheet. In another embodiment, the optical sheet may include only one diffusion sheet.

According to an aspect of the present invention, a liquid crystal display (LCD) is provided with a lamp for generating light, a light guide plate, a reflective sheet disposed below the light guide plate, at least one optical sheet disposed above the light guide plate, and an upper portion of the optical sheet. It includes a liquid crystal display panel for displaying an image. The light guide plate includes an incidence plane to which light from the lamp is incident, a first prism pattern formed to be spaced apart from each other, and a lower surface including a flat portion formed perpendicular to the incidence plane between the first prism patterns, and a second to be in contact with each other. It includes an upper surface on which the prism patterns are formed and has a shape in which the thickness decreases away from the incident surface.

According to the backlight assembly and the liquid crystal display device having the same, the manufacturing cost can be reduced by improving the brightness and reducing the optical sheet.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view showing a backlight assembly according to an embodiment of the present invention, Figure 2 is a combined cross-sectional view of the backlight assembly shown in FIG.

1 and 2, the backlight assembly 100 according to an embodiment of the present invention may include a lamp 110 generating light, a light guide plate 200 guiding a path of light generated from the lamp 110, and a light guide plate. The reflective sheet 120 is disposed below the 200, and the at least one optical sheet 130 is disposed above the light guide plate 200.

The lamp 110 is disposed at one side of the light guide plate 200. The lamp 110 generates light in response to a driving power source applied from an external inverter (not shown). The lamp 110 is formed of, for example, a cold cathode fluorescent lamp (CCFL) having an elongated cylindrical shape. In contrast, the lamp 110 may be formed of an external electrode fluorescent lamp (EEFL) in which electrodes are formed on outer surfaces of both ends.

The backlight assembly 100 may further include a lamp cover 112 that covers the three surfaces of the lamp 110 and protects the lamp 110. The lamp cover 112 may protect the lamp 110 and at the same time reflect the light generated by the lamp 110 toward the light guide plate 200 to improve light utilization efficiency.

The light guide plate 200 guides a traveling path of light incident from the lamp 110. The light guide plate 200 may be formed of a transparent material to prevent light loss. The light guide plate 200 is formed of, for example, polymethyl methacrylate (PMMA) or polycarbonate (PC) material.

The light guide plate 200 includes an incident surface 210 to which light from the lamp 110 is incident, a lower surface 220 connected to a lower side of the incident surface 210, and an upper surface 230 connected to an upper side of the incident surface 210. do. The light guide plate 200 has a wedge shape in which the thickness decreases as it moves away from the incident surface 210.

The lower surface 220 of the light guide plate 200 includes first prism patterns 250 and a flat portion 260.

The first prism patterns 250 are formed to be spaced apart from each other, and have a stripe shape formed in parallel with the incident surface 210. That is, the first prism patterns 250 are formed in a direction parallel to the length direction of the lamp 110. The first prism patterns 250 are formed at regular intervals, for example. In contrast, the first prism patterns 250 may be formed to have a smaller spacing from the incident surface 210 in order to improve the uniformity of luminance.

The flat part 260 is formed between the first prism patterns 250. The flat part 260 is formed perpendicular to the incident surface 210 so that the light guided in the light guide plate 200 satisfies the total reflection condition.

Therefore, the light incident into the light guide plate 200 through the incident surface 210 is totally reflected through the flat part 260, and the reflection angle is changed by the first prism pattern 250 to emit vertically toward the upper surface 230. do.

The first prism patterns 250 are transferred onto the lower surface 220 by an injection molding method. In addition, the first prism patterns 250 may be formed on the lower surface 220 by various methods such as a stamping method.

The upper surface 230 of the light guide plate 200 may include second prism patterns 270. The second prism patterns 270 are connected to each other, and have a stripe shape formed in a direction perpendicular to the first prism patterns 250.

Therefore, the light incident from the lamp 110 through the incident surface 210 is focused in the vertical direction by the first prism patterns 250 formed on the lower surface 220, and the light formed on the upper surface 230. Condensing in the horizontal direction is achieved by the two prism patterns 270.

The reflective sheet 120 is disposed on the lower surface 220 side of the light guide plate 200. The reflective sheet 120 reflects light leaking to the outside through the lower surface 220 of the light guide plate 200 and enters the light into the light guide plate 200 again. The reflective sheet 120 is made of a material having high light reflectance. For example, the reflective sheet 120 may be formed of white polyethylene terephthalate (PET) or white polycarbonate (PC) material.

The optical sheet 130 is disposed on the upper surface 230 side of the light guide plate 200 to improve the brightness of the light emitted from the light guide plate 200 or improve the appearance quality.

In the present embodiment, the optical sheet 130 includes one diffusion sheet 131. Since the diffusion sheet 131 has a certain amount of haze, bright lines, dark lines, and corners that may be generated by the first prism patterns 250 and the second prism patterns 270 of the light guide plate 200. It is possible to improve appearance quality problems such as dark areas. For example, the diffusion sheet 131 has a haze of about 50% to 70%. The diffusion sheet 131 may be formed of, for example, a 3M UTE film.

As such, by using only one diffusion sheet 131, two prism sheets and a protective sheet used in the conventional backlight assembly can be removed, thereby reducing manufacturing cost and reducing thickness and weight.

3 is an enlarged view illustrating in detail the first prism pattern illustrated in FIG. 2.

2 and 3, the first prism pattern 250 formed on the lower surface 220 of the light guide plate 200 is basically triangular in cross section in order to emit light traveling in the light guide plate 200 in a vertical direction. It is made of a groove having a shape.

The first prism pattern 250 includes a first inclined surface 252, a second inclined surface 254 connected to the first inclined surface 252, and a third inclined surface 256 connected to the second inclined surface 254.

The first inclined surface 252 is formed to be inclined in the direction of the upper surface 230 from the flat portion 260 of the previous stage. The second inclined surface 254 is inclined from the first inclined surface 252 toward the lower surface 220. The third inclined surface 256 extends in parallel with the first inclined surface 252 from the second inclined surface 254 and is connected to the subsequent flat portion 260.

The first inclined surface 252 and the second inclined surface 254 have a substantially symmetrical structure with respect to the normal NL of the flat portion 260.

The light guide plate 200 has a first thickness d1 at the incident surface 210, a second thickness d2 thinner than the first thickness d1 at the light facing surface 212, and the first prism pattern 250. The flat part 260 positioned between them has a structure perpendicular to the incident surface 210. Accordingly, the light guide plate 200 may have a thickness difference between a front end and a rear end based on the first prism pattern 250.

The first height h1 of the third inclined surface 256 corresponding to the difference in thickness between the front end and the rear end of the first prism pattern 250 may be obtained by Equation 1 below.

h1 = (d1-d2) / m

Here, d1 is a first thickness of the incident surface 210, d2 is a second thickness of the light facing surface 212, and m is a number of steps of the lower surface 220.

That is, the first height h1 of the third inclined surface 256 is determined according to the thickness difference between the incident surface 210 and the light facing surface 212 and the number of steps of the lower surface 240.

Meanwhile, the second height h2 of the first inclined surface 252, the bottom side a of the third inclined surface 256, and the bottom side b of the second inclined surface 254 are light guided in the light guide plate 200. This side emission is optimized so that no lost light is generated.

The first inclined surface 252 preferably has a height at which light that travels below the critical angle α based on the normal of the incident surface 210 does not reach the third inclined surface 256. Therefore, the second height h2 of the first inclined surface 252 can be obtained by the following equation (2).

h2 = h1 × [1 + tan (α) tan (β / 2)] / [1-tan (α) tan (β / 2)]

Here, α is a critical angle of the light guide plate 200, and β is an internal angle formed by the first inclined surface 252 and the second inclined surface 254.

In addition, the bottom side a of the third inclined surface 256 can be obtained by the following equation (3).

a = h1 × tan (β / 2)

In addition, the bottom side b of the second inclined surface 254 can be obtained by the following equation (4).

b = h2 x tan (β / 2)

Meanwhile, the inner angle β formed by the first inclined surface 252 and the second inclined surface 254 to emit light guided in the light guide plate 200 in a vertical direction may have a range of about 60 ° to about 90 °. have. Preferably, the inner angle β formed by the first inclined surface 252 and the second inclined surface 254 is formed at about 78 °.

In the case of the PMMA light guide plate which is most often used as the light guide plate 200, it has a critical angle α of about 42.16 °. For example, when the length from the incident surface 210 to the light facing surface 212 of the PMMA light guide plate is about 213 mm, and the pitch between the first prism patterns 250 is about 300 μm, the number of steps on the bottom surface 220 is shown. Becomes 710. At this time, when the first thickness d1 of the incident surface 210 of the PMMA light guide plate is about 2.6 mm and the second thickness d2 of the light facing surface 212 is about 0.7 mm, the thickness difference is about 1.9 mm. Therefore, according to Equation 1, the first height h1 of the third inclined surface 256 is about 2.68 μm. In addition, when the inner angle β between the first inclined surface 252 and the second inclined surface 254 is formed at about 78 °, the second height h2 of the first inclined surface 252 is about 17.38 by Equation 2. The bottom side a of the third inclined surface 256 is about 2.17 μm by Equation 3, and the bottom side b of the second inclined surface 254 is about 14.07 μm by Equation 4.

FIG. 4 is an enlarged view illustrating another embodiment of the first prism pattern shown in FIG. 2.

2 and 4, when the first prism pattern 350 is formed from the first inclined surface 352 and the first inclined surface 352 that are inclined toward the upper surface 230 from the flat portion 260 of the previous stage. A third inclined surface 356 extending in parallel with the first inclined surface 352 from the second inclined surface 354 and the second inclined surface 354 formed to be inclined in the direction of 220 and connected to the flat portion 260 of the subsequent stage. It includes.

The first slope 352 and the second slope 354 have a substantially asymmetrical structure with respect to the normal NL of the flat portion 260. For example, the bottom side a of the first inclined surface 352 is formed to be larger than the bottom side b of the second inclined surface 354. In particular, in order to increase the luminance, the bottom side a of the first inclined surface 352 and the bottom side b of the second inclined surface 354 may be formed at a ratio of about 4: 3.

The emission angle distribution of the light emitted through the upper surface 230 of the light guide plate 200 is influenced by the internal angle formed by the first inclined surface 352 and the second inclined surface 354. At this time, since the bottom side c of the first inclined surface 352 and the bottom side b of the second inclined surface 354 have different sizes, the normal line NL of the first inclined surface 352 and the flat portion 260 is different. The internal angle γ2 formed by the internal angle γ1, the second inclined surface 354, and the normal NL of the flat portion 260 has a different size.

In order to increase the distribution of the vertical emission light, the inner angle γ 1 formed between the first slope 352 and the normal line NL of the flat portion 260 may have a range of about 34 ° to about 44 °. Preferably, the inner angle γ 1 formed between the first slope 352 and the normal line NL of the flat portion 260 is formed at about 39 °.

FIG. 5 is an enlarged view illustrating still another embodiment of the first prism pattern illustrated in FIG. 2.

2 and 5, when the first prism pattern 450 is formed from the first inclined surface 452 and the first inclined surface 452 which are formed to be inclined toward the upper surface 230 from the flat portion 260 of the previous stage. The second inclined surface 454 formed to be inclined in the direction of 220, the connecting surface 456 extending in parallel with the flat portion 260 from the second inclined surface 454, and the first inclined surface 452 from the connecting surface 456. And a third inclined surface 458 extending in parallel to the flat portion 260 afterwards. The connection surface 456 is formed between the second inclined surface 454 and the third inclined surface 458 to improve transferability when the first prism pattern 450 is injection molded.

The first slope 452 and the second slope 454 have a substantially asymmetrical structure with respect to the normal NL of the flat portion 260. For example, the bottom c of the first inclined surface 452 may be larger than the bottom b of the second inclined surface 454. In particular, in order to increase the brightness, the bottom side c of the first inclined surface 452 and the bottom side b of the second inclined surface 454 may be formed at a ratio of about 4: 1. In this case, the width d of the connection surface 456 may be formed to about 3/4 of the base c of the first inclined surface 452.

FIG. 6 is an enlarged view illustrating still another embodiment of the first prism pattern illustrated in FIG. 2.

2 and 6, when the first prism pattern 550 is formed from the first inclined surface 552 and the first inclined surface 552 that are inclined toward the upper surface 230 from the flat portion 260 of the previous stage. The second inclined surface 554 formed to be inclined in the direction of 220, the connecting surface 556 extending in parallel with the flat portion 260 from the second inclined surface 554, and the first inclined surface 552 from the connecting surface 556. It may include a third inclined surface 558 extending in parallel with and connected to the flat portion 260 of the subsequent stage.

The first slope 552 and the second slope 554 have a substantially asymmetrical structure with respect to the normal NL of the flat portion 260. For example, the bottom side c of the first inclined surface 552 is formed larger than the bottom side b of the second inclined surface 554. In particular, in order to increase the luminance, the bottom side c of the first inclined surface 552 and the bottom side b of the second inclined surface 554 may be formed at a ratio of about 4: 1.

In order to prevent the loss of light through the third inclined surface 558 as much as possible, it is preferable that the connection surface 556 has a width as small as possible within the range that does not affect the transferability of the first prism pattern 550. Do. For example, the width d of the connection surface 556 may be formed to be about 1/4 of the base c of the first inclined surface 552.

FIG. 7 is an enlarged view illustrating a portion of the light guide plate illustrated in FIG. 1.

Referring to FIG. 7, a plurality of second prism patterns 270 are formed on the upper surface 230 of the light guide plate 200. The second prism patterns 270 are formed over the entire surface of the upper surface 230.

The second prism patterns 270 are formed in a direction perpendicular to the longitudinal direction of the lamp 110, that is, in a direction perpendicular to the incident surface 210. Therefore, the first prism patterns 250 and the second prism patterns 270 are formed in a direction perpendicular to each other.

The second prism patterns 270 have a substantially triangular cross section perpendicular to the length direction. The vertex angle θ of the second prism patterns 270 may be formed in a range of about 80 degrees to about 150 degrees. Preferably, the vertex angle θ of the second prism patterns 270 is formed at about 110 degrees. The pitch P between the second prism patterns 270 may be formed in a range of about 50 μm to about 150 μm.

Meanwhile, an upper end of the second prism patterns 270, that is, an edge portion where two inclined surfaces meet may have a curved shape. In addition, the second prism patterns 270 may have a curved shape.

8 is an exploded view showing a backlight assembly according to another embodiment of the present invention. In FIG. 8, the rest of the configuration except for the optical sheet has the same configuration as that shown in FIG. 1, and the same reference numerals are used for the same components, and detailed description thereof will be omitted.

Referring to FIG. 8, the optical sheet includes one prism sheet 132. Third prism patterns 133 are formed on the upper surface of the prism sheet 132 to be in contact with each other. The third prism patterns 133 have a stripe shape formed in a direction parallel to the second prism patterns 270 formed on the upper surface 230 of the light guide plate 200. In contrast, the third prism patterns 133 may have a stripe shape formed in a direction perpendicular to the second prism patterns 270. For example, the prism sheet 132 may be formed of 3M BEF3.

The third prism patterns 133 may have a substantially triangular cross section perpendicular to the length direction. The vertex angles of the third prism patterns 133 may be formed in a range of about 80 degrees to about 150 degrees. Meanwhile, an upper end of the third prism patterns 133, that is, an edge portion where two inclined surfaces meet may have a curved shape. In addition, the third prism patterns 133 may have a curved shape.

Thus, by using only one prism sheet 132 as an optical sheet, it is possible to improve the appearance quality problems such as bright lines, dark lines, and corner arms, and to significantly improve the luminance as compared with the case of using only the diffusion sheet. .

9 is an exploded perspective view illustrating a backlight assembly according to another embodiment of the present invention. In FIG. 9, since the rest of the configuration except for the protective sheet has the same configuration as that shown in FIG. 8, the same reference numerals are used for the same components, and detailed description thereof will be omitted.

Referring to FIG. 9, the optical sheet includes one prism sheet 132 and one protective sheet 134. The protective sheet 134 may be disposed on the prism sheet 132 to protect the prism sheet 132 and to prevent adhesion to the liquid crystal display panel disposed above, thereby further improving the reliability of appearance quality. . The protective sheet 134 has a haze of about 70% to 90%, for example.

Table 1 shows data obtained by measuring optical characteristics of the liquid crystal display device according to the configuration of the optical sheet. In Table 1, the comparative example is a case where a diffusion sheet, two prism sheets, and a protective sheet are used on the light guide plate on which the first and second prism patterns are not formed, and the first embodiment is the first embodiment as shown in FIG. And one diffusion sheet is used on the light guide plate on which the second prism pattern is formed, and the second embodiment uses one prism sheet on the light guide plate on which the first and second prism patterns are formed, as shown in FIG. 8. The third embodiment is a case where the prism sheet and the protective sheet are used on the light guide plate on which the first and second prism patterns are formed, as shown in FIG. 9.

TABLE 1

Comparative example First embodiment Second embodiment Third embodiment 5-point average brightness (nit) 176 166 216 215 Luminance Ratio (%) 100.0 94.2 123.1 122.2 5-point luminance uniformity (%) 92.2 93.2 86.8 86.9

Referring to Table 1, in the case of the first embodiment using only one diffusion sheet, the average brightness is slightly lower than that of the comparative example using four optical sheets, but three optical sheets can be reduced. This can reduce the cost of the product and reduce the thickness and weight.

In the case of the second and third embodiments in which only one prism sheet is used or one prism sheet and one protective sheet is used, although the luminance uniformity is somewhat lower than that of the first embodiment, the comparative example is slightly lower than that of the comparative example. It can be seen that the luminance of about 23% is increased, and the luminance of about 30% is increased compared to the first embodiment. Therefore, according to the second embodiment and the third embodiment, the average brightness can be increased as compared with the comparative example, and the optical sheet can be reduced to reduce thickness, weight, and product cost.

10 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 10, the liquid crystal display 600 includes a backlight assembly 100 that supplies light and a display unit 700 that displays an image by using light supplied from the backlight assembly 100.

The backlight assembly 100 may include a lamp 110 generating light, a light guide plate 200 guiding a path of light generated from the lamp 110, a reflective sheet 120 disposed below the light guide plate 200, and a light guide plate 200. At least one optical sheet 130 disposed on the top). The backlight assembly 100 may have any one of various embodiments shown in FIGS. 1 to 9. Therefore, detailed description thereof will be omitted.

The display unit 700 includes a liquid crystal display panel 710 for displaying an image using light supplied from the backlight assembly 100, and a driving circuit unit 720 for driving the liquid crystal display panel 710.

The liquid crystal display panel 710 is disposed above the optical sheet 130. The liquid crystal display panel 710 includes a first substrate 712, a second substrate 714 coupled to the first substrate 712, and a liquid crystal interposed between the first substrate 712 and the second substrate 714. Layer (not shown).

The first substrate 712 may be a TFT substrate in which a thin film transistor (hereinafter, referred to as a TFT) as a switching element is formed in a matrix form. A data line and a gate line are respectively connected to the source terminal and the gate terminal of the TFTs, and a pixel electrode made of a transparent conductive material is connected to the drain terminal.

The second substrate 714 may be a color filter substrate in which RGB pixels for implementing colors are formed in a thin film form. The common electrode made of a transparent conductive material is formed on the second substrate 714. Meanwhile, the color filter may be formed on the first substrate 712.

In the liquid crystal display panel 710 having such a configuration, when power is applied to the gate terminal of the TFT and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. By the electric field, the arrangement of liquid crystal molecules of the liquid crystal layer interposed between the first substrate 712 and the second substrate 714 is changed, and the transmittance of light supplied from the backlight assembly 100 is changed according to the arrangement change of the liquid crystal molecules. The image is changed to display an image of a desired gradation.

The driving circuit 720 includes data connecting the source printed circuit board 721 to output various control signals for driving the liquid crystal display panel 710, and the source printed circuit board 721 and the liquid crystal display panel 710. The driving circuit film 723 and the gate driving circuit film 725 connected to the liquid crystal display panel 710 may be included.

The data driving circuit film 723 is connected to the data line of the first substrate 712, and the gate driving circuit film 725 is connected to the gate line of the first substrate 712. The data driving circuit film 723 and the gate driving circuit film 725 include driving chips for outputting driving signals for driving the liquid crystal display panel 710 in response to control signals supplied from the source printed circuit board 721. can do. The data driving circuit film 723 and the gate driving circuit film 725 are formed of, for example, a tape carrier package (TCP) or a chip on film (COF).

Although not shown, the driving circuit unit 720 may further include a gate printed circuit board connected to the gate driving circuit film 725.

According to the backlight assembly and the liquid crystal display having the same, by disposing only one diffusion sheet on the light guide plate on which the prism patterns are formed on the lower surface and the upper surface, it is possible to reduce product cost and reduce thickness and weight without degrading the product performance. Can be.

In addition, by using only one prism sheet on the light guide plate on which the prism patterns are formed on the lower surface and the upper surface, or by using one prism sheet and one protective sheet, the brightness is increased and the optical sheet is reduced to reduce thickness, weight and product. Cost can be reduced.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (21)

A lamp for generating light; An incident surface to which light from the lamp is incident, a first prism pattern formed to be spaced apart from each other, and a lower surface including a flat portion formed perpendicularly to the incident surface between the first prism patterns, and a second prism pattern connected to each other A light guide plate including an upper surface on which they are formed; A reflective sheet disposed under the light guide plate; And And at least one optical sheet disposed on the light guide plate. The backlight assembly of claim 1, wherein the light guide plate decreases in thickness as it moves away from the incident surface. The backlight assembly of claim 2, wherein the first prism patterns have a stripe shape formed in parallel with the incident surface. The method of claim 3, wherein the first prism pattern is A first inclined surface formed to be inclined from the flat portion in the upper surface direction; A second inclined surface inclined from the first inclined surface toward the lower surface; And And a third inclined surface extending from the second inclined surface in parallel with the first inclined surface and connected to the flat portion. The backlight assembly of claim 4, wherein the second prism patterns have a stripe shape formed in a direction perpendicular to the first prism patterns. The backlight assembly of claim 5, wherein a vertex of the second prism pattern is 80 degrees to 150 degrees. The backlight assembly of claim 5, wherein the optical sheet comprises a prism sheet having upper surfaces of third prism patterns that are in contact with each other. The backlight assembly of claim 7, wherein the third prism patterns have a stripe shape formed in a direction parallel to the second prism patterns. The backlight assembly of claim 7, wherein the third prism patterns have a stripe shape formed in a direction perpendicular to the second prism patterns. The backlight assembly of claim 7, wherein a vertex of the third prism pattern is 80 degrees to 150 degrees. The backlight assembly of claim 7, wherein the bottom surface of the prism sheet is matted. The backlight assembly of claim 7, wherein the optical sheet further comprises a protective sheet disposed on the prism sheet. 6. The backlight assembly of claim 5, wherein the optical sheet comprises a diffusion sheet. The backlight assembly of claim 5, wherein the first inclined surface and the second inclined surface have a substantially symmetrical structure with respect to the normal of the flat portion. The backlight assembly of claim 5, wherein the first inclined surface and the second inclined surface have a substantially asymmetrical structure with respect to the normal of the flat portion. The backlight assembly of claim 15, wherein a bottom side of the first inclined surface is greater than a bottom side of the second inclined surface. The backlight assembly of claim 16, wherein the first prism pattern further comprises a connection surface formed parallel to the flat portion between the second slope and the third slope. A lamp for generating light; An incidence surface to which light from the lamp is incident, a lower surface including first prism patterns spaced apart from each other and a flat portion formed perpendicularly to the incidence surface between the first prism patterns; A light guide plate including an upper surface on which second prism patterns are formed in a direction perpendicular to the first prism patterns, the thickness of which decreases as the distance from the incident surface increases; A reflective sheet disposed under the light guide plate; At least one optical sheet disposed on the light guide plate; And And a liquid crystal display panel disposed on the optical sheet to display an image. 19. The liquid crystal display device according to claim 18, wherein the optical sheet comprises a prism sheet. 20. The liquid crystal display device according to claim 19, wherein the optical sheet further comprises a protective sheet disposed on the prism sheet. 19. The liquid crystal display device according to claim 18, wherein the optical sheet comprises a diffusion sheet.

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