KR20150069324A - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more specifically, to a liquid crystal display device including a backlight unit having improved light efficiency, and to a method for manufacturing a light guide plate. As a dot pattern is formed on an upper surface of the light guide plate and a reverse prism mountain condensing sheet is located at the top of the light guide plate, polarizing properties of specific linear polarized light arriving in the light guide plate through a reflection polarizing film can be maintained. Also, front light output ratio of the light guide plate can be improved so that surface light sources of high brightness can be provided as a liquid crystal panel.

Description

[0001] Liquid crystal display device [0002]

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a backlight unit with improved light efficiency.

In recent years, the display field has been rapidly developed in line with the information age. In response to this trend, a flat panel display device (FPD) having advantages of thinning, light weight and low power consumption has been developed. A plasma display panel (PDP), an electroluminescence display device (ELD), and a field emission display device (FED) tube: CRT).

In particular, the liquid crystal display device is superior in moving picture display and is most actively used in the fields of notebook computers, monitors, and TVs due to its high contrast ratio. The liquid crystal display device is an element that does not have a self- .

Accordingly, a backlight unit having a light source is provided on the back surface of the liquid crystal panel, and light is emitted toward the front surface of the liquid crystal panel, thereby realizing an image of brightness that can be recognized only through the backlight unit.

Meanwhile, a general backlight unit is divided into a side light type and a direct type type according to the arrangement structure of the light sources. In the sidelight type, one or a pair of light sources are disposed on one side of the light guide plate Or two or two light sources are disposed on both side portions of the light guide plate, and the direct type system has a structure in which several light sources are disposed under the optical sheet.

Here, the sidelight method is advantageous in that it is easier to manufacture than the direct-type method, and is thinner than the direct-type type, has a light weight, and has low power consumption.

1 is a cross-sectional view of a liquid crystal display device using a general sidelight type backlight unit.

As shown in the figure, a typical liquid crystal display device includes a liquid crystal panel 10, a backlight unit 20, a guide panel 30, a cover bottom 50, and a top cover 40.

The liquid crystal panel 10 is constituted by first and second substrates 12 and 14 which are in contact with each other with a liquid crystal layer interposed therebetween, which plays a key role in image display. A printed circuit board (not shown) is connected to each of the two adjacent edges of the liquid crystal panel 10 through a connection member (not shown).

At this time, polarizing plates 19a and 19b for selectively transmitting only specific light are attached to the outer surfaces of the first and second substrates 12 and 14 of the liquid crystal panel 10, respectively.

A backlight unit 20 is provided behind the liquid crystal panel 10.

The backlight unit 20 includes an LED assembly 29 arranged along the longitudinal direction of at least one edge of the guide panel 30, a white or silver reflective plate 25 seated on the cover bottom 50, 25, and an optical sheet 21 interposed therebetween.

Here, the LED assembly 29 includes a plurality of LEDs 29a and a PCB 29b on which a plurality of LEDs 29a are mounted.

The liquid crystal panel 10 and the backlight unit 20 are covered with a top cover 40 covering the top edge of the liquid crystal panel 10 with the edges thereof being surrounded by a rectangular guide panel 30, The cover bottoms 50 are integrally joined to each other through the guide panel 30.

The light emitted from the LED assembly 29 is incident on the light guide plate 23 and then refracted in the direction of the liquid crystal panel 10 and processed to a high quality of uniform luminance while passing through the optical sheet 21, So that the liquid crystal panel 10 displays an image on the outside.

On the other hand, in such a liquid crystal display device, some of the light emitted from the backlight unit 20 is absorbed and reflected by the first polarizer 19a and is lost, which corresponds to 50% of the light emitted from the backlight unit 20 .

In addition, since the liquid crystal layer is absorbed and reflected during the process of passing through the liquid crystal layer (not shown) including the first and second substrates 12 and 14 and a part thereof is lost again, the liquid crystal display panel has a weak point in terms of brightness.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a liquid crystal display device having a high luminance by minimizing optical loss and improving light efficiency of a liquid crystal display device. .

A third object of the present invention is to maintain the polarization characteristics incident on the inside of the light guide plate.

Particularly, the fourth object is to allow high-luminance light to be emitted from the light guide plate.

In order to achieve the object as described above, the present invention provides a liquid crystal display comprising: a reflection plate; A light guide plate mounted on the reflection plate and having a dot pattern formed on an upper surface thereof; An LED assembly arranged along the light incident surface of the light guide plate; An optical sheet mounted on the light guide plate and including an inverse prism sheet condensing sheet; And a liquid crystal panel mounted on the optical sheet.

At this time, a reflective polarizing film is positioned between the light incidence surface and the LED assembly, and the reflective polarizing film is composed of a multilayer thin film structure in which a polarizer is embedded in a laminated structure of dielectric thin films having different refractive indexes, And a wire grid reflective polarizing film comprising a fine metal pattern.

The dot pattern has a convex shape and is distributed and arranged in a spaced apart relation with a diameter of 10 to 500 μm and a height of 1/2 ± 10 of the diameter, and the dot pattern is shifted from the light- And is formed at a high density per unit area.

The plurality of prism mountains are arranged in a strip shape in which the prisms are repeatedly arranged along the longitudinal direction of the LED assembly.

As described above, according to the present invention, a dot pattern is formed on the upper surface of the light guide plate, and the reverse prism sheet is positioned on the upper side of the light guide plate, so that the polarizing characteristic of the specific linearly polarized light incident into the light guide plate through the reflective polarizing film It is possible to maintain the same.

Further, the forward light emission rate of the light guide plate can be improved, and a surface light source of higher luminance can be provided to the liquid crystal panel.

1 is a sectional view of a liquid crystal display device using a general sidelight type backlight unit.
2 is an exploded perspective view of a liquid crystal display device according to the present invention.
Fig. 3 is an exploded perspective view schematically showing the backlight unit of Fig. 2; Fig.
Figs. 4A to 4B are schematic diagrams schematically showing Fig. 3. Fig.
FIG. 5 is a simulation result of measuring the polarized light transmittance and the upper surface light transmittance of the light guide plate according to the aspect ratio of the dot pattern.
Fig. 6 is a cross-sectional view schematically showing a partial cross section of Fig. 2 modularized; Fig.

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

2 is an exploded perspective view of a liquid crystal display device according to the present invention.

As shown, the liquid crystal display device includes a liquid crystal panel 110, a backlight unit 120, a guide panel 130, a cover bottom 150, and a top cover 140.

First, the liquid crystal panel 110 plays a key role in image display and includes first and second substrates 112 and 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

At this time, a plurality of gate lines and data lines intersect with each other on the inner surface of the first substrate 112, which is usually referred to as a lower substrate or an array substrate, although not clearly shown in the figure, And a thin film transistor (TFT) is provided at each of the intersections, and is connected in a one-to-one correspondence with the transparent pixel electrodes formed in the respective pixels.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, color filters of red (R), green (G), and blue (B) And a black matrix for covering non-display elements such as a gate line, a data line, and a thin film transistor. In addition, a transparent common electrode covering these elements is provided.

A gate and a data printed circuit board 117 are connected to each other via a connection member 116 such as a flexible circuit board along at least one edge of the liquid crystal panel 110, (150).

Although not clearly shown in the drawing, an alignment film for determining the initial alignment direction of the liquid crystal is interposed at the boundary between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer, and a liquid crystal layer A seal pattern is formed along edges of both the substrates 112 and 114 to prevent leakage of the substrate.

At this time, the first and second polarizers 119a and 119b (see FIG. 6) are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A backlight unit 120 for supplying light to the back surface of the liquid crystal panel 110 is provided so that a difference in transmittance represented by the liquid crystal panel 110 is externally manifested.

The backlight unit 120 includes an LED assembly 129 and a reflective polarizing film 210 arranged in the longitudinal direction of at least one edge of the guide panel 130, a white or silver reflective plate 125, And an optical sheet 121 interposed between the light guide plate 220 and the light guide plate 220.

The LED assembly 129 described above is a light source of the backlight unit 120 and is disposed on one side of the light guide plate 220 so as to face the light incident surface 221a of the light guide plate 220. The LED assembly 129, Includes a plurality of LEDs 129a and a PCB 129b on which a plurality of LEDs 129a are mounted with a predetermined distance therebetween.

A bar-shaped reflective polarizing film 210 is positioned in front of the LED 129a of the LED assembly 129. The reflective polarizing film 210 reflects only a specific linearly polarized light among the light emitted from the LED 129a And the remaining light is reflected and reproduced, thereby further improving the light efficiency of the liquid crystal display device of the present invention.

The light guide plate 220 through which the specific linearly polarized light transmitted through the reflective polarizing film 210 enters enters the liquid crystal panel 110 by spreading the light guide plate 220 evenly over the wide area of the light guide plate 220, To provide a surface light source.

In particular, in the light guide plate 220 according to the embodiment of the present invention, the hemispherical dot pattern 223 is formed on the upper surface 221e (see FIG. 3), whereby the liquid crystal display device of the present invention includes the reflective polarizing film 210 The polarization characteristic of the specific linearly polarized light incident into the light guide plate 220 can be kept constant through the light guide plate 220 and a large amount of light can be emitted forward of the light guide plate 220.

The reflection plate 125 is disposed on the back surface of the light guide plate 220 and reflects light passing through the lower surface 220d of the light guide plate 220 (see FIG. 3) toward the liquid crystal panel 110, thereby improving the brightness of light.

The optical sheet 121 on the light guide plate 220 includes a diffusion sheet and at least one light condensing sheet 230 to diffuse or condense the light passing through the light guide plate 220 to form a more uniform surface Allow the light source to enter.

At this time, the light collecting sheet 230 is composed of an inverted prism light collecting sheet in which a plurality of prism mountains 231 (see FIG. 3) are protruded and arranged toward the light guide plate 220.

As a result, a high-brightness surface light source can be provided to the liquid crystal panel 110. Let me take a closer look at this later.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the guide panel 130 and the cover bottom 150. The top cover 140 is disposed on the top edge of the liquid crystal panel 110, So as to cover the side surface.

Here, the top cover 140 has a rectangular frame shape bent in a "? &Quot; shape so as to cover the top and side edges of the liquid crystal panel 110, As shown in Fig.

The cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are mounted and is a basis for assembling the entire structure of the liquid crystal display device is composed of a horizontal plane 151 and an edge portion 153 whose edges are vertically bent .

A rectangular guide panel 130 mounted on the cover bottom 150 and covering the edges of the liquid crystal panel 110 and the backlight unit 120 includes a top cover 140 and a cover bottom 150, .

Here, the top cover 140 may be referred to as a case top or a top case, and the guide panel 130 may be referred to as a support main or main support or a mold frame. The cover bottom 150 may be referred to as a bottom cover or a bottom cover I will.

At this time, the liquid crystal display of the above-described structure can eliminate the top cover 140 and the cover bottom 150 in order to realize a lightweight and thin liquid crystal display device which is recently required. The liquid crystal display device can be made light and thin by eliminating the top cover 140 and the cover bottom 150, and the process can be simplified.

In addition, the elimination of the cover cover 140 and the cover valve 150, which are made of a metal material, can reduce the process cost.

As described above, in the liquid crystal display device of the present invention, the hemispherical dot pattern 223 is formed on the upper surface 220e (see Fig. 3) of the light guide plate 220, and the optical sheet 121 is directed toward the light guide plate 220 The polarizing characteristic of the specific linearly polarized light incident into the light guide plate 220 is maintained through the reflective polarizing film 210 by including the inverse prism condensing sheet 230 in which a plurality of prism mountains 231 And at the same time, a large amount of light can be emitted toward the front of the light guide plate 220.

As a result, a high-brightness surface light source can be provided to the liquid crystal panel 110.

Fig. 3 is an exploded perspective view schematically showing the backlight unit of Fig. 2, and Figs. 4a to 4b are schematic diagrams schematically showing Fig.

3, the backlight unit 120 includes an LED assembly 129 including a LED 129a as a light source and a PCB 129b on which the LED 129a is mounted, and an LED assembly 129, A reflecting plate 125 positioned below the light guide plate 220 and an optical sheet 121 positioned on the upper side of the light guide plate 220. The light guide plate 220 is disposed to face the light guide plate 220,

A bar-shaped reflective polarizing film 210 is positioned between the LED assembly 129 and the light incident surface 221a of the light guide plate 220. [

At this time, the plurality of LEDs 129a include an LED chip (not shown) that emits all the RGB colors or emits white light, and emits white light toward the light incoming surface 221a of the light guide plate 220 forward. The plurality of LEDs 129a emit light having colors of red (R), green (G) and blue (B), respectively. By lighting the plurality of RGB LEDs 129a at once, white light It can also be implemented.

4A and 4B, the reflective polarizing film 210 is formed to have the same polarization axis as the polarizing axis of the first polarizing plate 119a positioned below the liquid crystal panel (110 of FIG. 2) The light transmitted through the reflective polarizing film 210 and incident into the light guide plate 220 is emitted to the outside of the light guide plate 220 and provided to the liquid crystal panel 110 119a and is provided to the liquid crystal panel (110 in Fig. 2).

That is, the light emitted from the backlight unit 120 is transmitted through the first polarizing plate 119a only by the first polarizing plate 119a having the same polarization axis as the polarization axis of the first polarizing plate 119a, The liquid crystal display device according to the present invention includes a reflective polarizing film 210 having the same polarization axis as that of the first polarizing plate 119a in front of the LED 129a of the LED assembly 129 , So that only the light having the same polarization axis as the polarization axis of the first polarizing plate 119a is emitted from the backlight unit 120.

Accordingly, the transmittance of the first polarizer 119a is improved, thereby increasing the amount of light supplied to the liquid crystal panel 110 (FIG. 2), thereby achieving high brightness.

The light guide plate 220 may be formed of a plastic material such as polymethylmethacrylate (PMMA) or polycarbonate (PC), which is an acrylic transparent resin, which is one of transparent materials capable of transmitting light. PMMA is widely used because it has excellent transparency, weatherability and colorability and induces diffusion of light when light is transmitted.

The light guide plate 220 includes a light incident surface 221a corresponding to the LED assembly 129a and a light incident surface 221b corresponding to the light incident surface 221a and a light incident surface 221a and a light incident surface 221b, A lower surface 221f facing the surface 221e and the reflection plate 125 and opposite side surfaces 211c and 211d facing each other.

The light guide plate 220 may include a pattern of a specific shape on the lower surface to supply a uniform surface light source. Here, the pattern may be formed in various shapes such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like in order to guide light incident into the light guide plate 220. The pattern is formed on the lower surface of the light guide plate 220 by a printing method or an injection method.

A hemispherical dot pattern 223 is protruded from the upper surface 221e of the light guide plate 220.

A plurality of dot patterns 223 are distributed on the upper surface 221e of the light guide plate 220 so as to be spaced apart from each other at a predetermined interval. At this time, the dot pattern 223 is formed to have a diameter of 10 to 500 μm, It is preferable that the height of the protrusion 223 is formed to have a height corresponding to 1/2 10% of the diameter.

That is, the dot pattern 223 may be formed to have a diameter of 100 μm, and the height of the dot pattern 223 is formed to be 50 μm.

FIG. 5 is a simulation result of measurement of the polarized light transmittance and the upper surface light emission rate of the light guide plate according to the aspect ratio of the dot pattern.

Here, the aspect ratio is a ratio of the height to the radius of the dot pattern. Referring to FIG. 5, it can be seen that the closer the aspect ratio is to 1, the more the polarized light transmittance is improved.

At this time, the dot pattern 223 is formed at a high density per unit area as the LED assembly 129 is positioned and the light from the light-entering surface 221a to the light-receiving surface 221b to which the reflective polarizing film 210 is attached.

That is, the density of the dot patterns 223 is formed denser toward the light receiving surface 221b of the light guide plate 220 from the light incident surface 221a of the light guide plate 220 where the LED assembly 129 is located.

When the LED assembly 129 as the light source is located only on the light incidence surface 221a side of the light guide plate 220, the liquid crystal panel 110 of FIG. 2 is provided on the light incidence surface 221a side of the light guide plate 220, The amount of light emitted toward the liquid crystal panel (110 in FIG. 2) is greater than the amount of light emitted toward the liquid crystal panel (110 in FIG. 2) from the side of the light incoming surface 221b of the light guide plate 220, . ≪ / RTI >

At this time, the more the dot pattern 223 formed on the upper surface 221e of the light guide plate 220, the closer the light incident into the light guide plate 220 toward the liquid crystal panel (110 in FIG. 2).

The dot pattern 223 formed on the upper surface 221e of the light guide plate 220 is formed at a high density per unit area from the light incidence surface 221a toward the light incident surface 221b, 2) of the light guide plate 220 and the amount of light emitted toward the liquid crystal panel (110 of FIG. 2) from the side of the light-incoming surface 221b of the light guide plate 220 can be formed to be equal to each other It is.

Accordingly, light of a uniform brightness can be emitted from the light guide plate 220, and a uniform planar light source can be incident on the liquid crystal panel (110 of FIG. 2).

The optical sheet 121 positioned above the light guide plate 220 is composed of a diffusion sheet and at least one light condensing sheet 230. The light condensing sheet 230 is disposed on the light guide plate 220, And an inverse prism condensing sheet in which the prisms 231 are protruded and arranged.

In other words, the light collecting sheet 230 is arranged on the back of the light collecting sheet 230 in a direction transverse to the longitudinal direction of the light collecting sheet 230 corresponding to one edge of the LED assembly 129, A plurality of prism mountains 231 protrude from the back surface.

Therefore, the liquid crystal display of the present invention can maintain the polarization characteristic of the specific linearly polarized light incident into the light guide plate 220 through the reflective polarizing film 210, and can further improve the light output efficiency of the light guide plate 220 Can be implemented.

The light emitted from the LED 129a of the LED assembly 129 is reflected by the reflective polarizing film 210 positioned in front of the LED assembly 129 so that only a specific linearly polarized light is emitted into the light guide plate 220 At this time, a large amount of light is reflected by the inside of the light guide plate 220 and the reflection plate 125, and the polarization characteristic of the specific linearly polarized light changes.

However, according to the present invention, the dot pattern 223 is formed on the upper surface 221e of the light guide plate 220, and the light guide sheet 230 among the optical sheets 121 located on the upper side of the light guide plate 220, The polarizing characteristic of the linearly polarized light can be maintained in the light guide plate 220 without being changed by the prism sheet 231 in which the prism mountains 231 are protruded toward the upper surface of the light guide plate 220, The luminous flux can be improved.

Table 1 below shows the results of comparing the polarization degree of the conventional backlight unit and the backlight unit 120 according to the embodiment of the present invention.

division Polarization degree Conventional backlight unit 20 to 36% The backlight unit according to the embodiment of the present invention 90% ↑

Here, the degree of polarization (DOP) means the ratio of the transmittance of the polarizing plate capable of expressing the retention of the polarization characteristic of the light emitted from the light guide plate. DOP = (TE-TM) / (TE + TM) * 100 (Where TE represents the transverse electric wave and TM the transverse magnetic wave).

Referring to the table (1), it can be seen that, even in the case of the conventional backlight unit, even when specific linearly polarized light enters into the LGP, only 20 to 36% of the light supplied to the liquid crystal panel maintains the specific linear polarization.

On the other hand, as in the embodiment of the present invention, the dot pattern 223 is formed on the upper surface 221e of the light guide plate 220 and the inverted prism sheet 230 is positioned on the upper side of the light guide plate 220, It is confirmed that the degree of polarization (= polarization maintaining ratio) of the unit 120 is maintained at 90% or more.

Accordingly, the backlight unit 120 of the present invention can keep the polarization characteristics of the specific linearly polarized light incident into the light guide plate 220 unchanged.

Thus, by emitting the light having the uniform polarization characteristic from the light guide plate 220, it is possible to provide all the light emitted from the backlight unit 120 to the liquid crystal panel (110 in FIG. 2) without loss of light, Can be implemented.

Table 2 below shows comparison data between the outgoing light flux of the upper surface 220e of the light guide plate 220 on which the dot pattern 223 is formed according to the embodiment of the present invention.

division Top beam output Conventional light guide plate 50 to 52% The light guide plate including the dot prism pattern according to the first embodiment of the present invention 95% ↑

Referring to Table 2 and FIG. 5, the conventional light guide plate has only about 50 to 52% of light emitted to the front of the light guide plate, even when 100% of light is incident from the LED assembly into the light guide plate.

However, since the dot pattern 223 is formed on the upper surface 221e of the light guide plate 220 and the reverse prism sheet 230 is disposed on the upper side of the light guide plate 220 as in the embodiment of the present invention, The light of 95%, which is the majority of the light incident to the inside of the light guide plate 220, is emitted to the front of the light guide plate 220.

This is improved by about 40% or more as compared with the conventional light guide plate.

That is, the light guide plate 220 of the present invention has the dot pattern 223 formed on the upper surface 221e and the inverted prism sheet 230 on the upper side of the light guide plate 220, So that the forward light emission rate is maximized with respect to the light totally reflected.

Thus, a liquid crystal panel (110 in FIG. 2) provides a higher brightness surface light source.

Fig. 6 is a cross-sectional view schematically showing a part of the section of Fig. 2 modularized.

An LED assembly 129 composed of a reflective plate 125, a light guide plate 220, a PCB 129b on which the LED 129a and the LED 129a are mounted, and an optical sheet (not shown) on the light guide plate 220, 121 are stacked to form a backlight unit (120 of FIG. 3).

A liquid crystal panel 110 in which a liquid crystal layer (not shown) is interposed between the first and second substrates 112 and 114 and the backlight unit 120 (FIG. 3) Polarizers 119a and 119b for selectively transmitting only specific light are attached to the outer surfaces of the two substrates 112 and 114, respectively.

The backlight unit 120 and the liquid crystal panel 110 are surrounded by the guide panel 130 and a cover bottom 150 formed of a horizontal surface 151 and a side surface 153 is coupled to the back surface of the backlight unit 120 A top cover 140 covering the upper surface edge and the side surface of the liquid crystal panel 110 is coupled to the guide panel 130 and the cover bottom 150.

3, the reflective polarizing film 210 is interposed between the LED 129a and the light incident surface 220a of the light guide plate 220, so that the light emitted from the LED 129a is transmitted through the light- .

Here, the reflective polarizing film 210 may include a polarizer having a certain polarization axis in a laminated structure of dielectric thin films exhibiting different refractive indices, or may be formed of aluminum (Al), silver (Ag), chrome And a wire grid polarizer in which fine linear metal patterns such as chromium (Cr) are arranged side by side in one direction.

The reflective polarizing film 210 transmits a part of the incident light and reflects the remaining light. The reflected light is reproduced as scattered light. Some of the reproduced scattered light transmits again through the reflective polarizing film 210 and the remaining light is reflected again.

Therefore, the reproduction of light is continuously repeated, and as a result, the light efficiency is improved.

That is, the first polarized light emitted from the LED 129a is transmitted through the reflective polarizing film 210 and enters the light guide plate 220 through the light entrance surface 220a of the light guide plate 220. However, A second polarized light is reflected by the reflective polarizing film 210 and then reproduced as scattered light.

The first polarized light of the light reproduced by the scattered light is again transmitted through the reflective polarizing film 210 and the second polarized light is reproduced by the scattered light again to improve the light efficiency.

At this time, the reflective polarizing film 210 has the same polarization axis as the first polarizing plate 119a attached to the lower portion of the liquid crystal panel 110, so that the first polarized light 119a transmitted through the reflective polarizing film 210 is incident on the light guide plate 220, and is emitted from the planar light source toward the liquid crystal panel 110 by total internal reflection in the light guide plate 220. At this time, all the planar light sources emitted from the light guide plate 220 are made of the first polarized light, The first polarizer 119a located under the panel 110 is directly transmitted.

Therefore, among the planar light sources emitted from the light guide plate 220, no light is lost by the first polarizer 119a, and high brightness can be realized.

3, the dot pattern 223 is formed on the upper surface 221e of the light guide plate 220 and the optical sheet 121 is guided toward the light guide plate 220 by a plurality of prism mountains The polarizing characteristic of the specific linearly polarized light incident into the light guide plate 220 through the reflective polarizing film 210 can be maintained by including the inverted prism sheet 230 in which the light guide plate 231 protrudes.

Thus, by emitting light having uniform polarization characteristics from the light guide plate 220, it is possible to provide all the light emitted from the backlight unit (120 in FIG. 3) to the liquid crystal panel 110 without loss of light, Can be implemented.

In addition, the luminous efficiency of the upper surface 221e of the light guide plate 220 can be improved, and a surface light source of higher brightness can be provided to the liquid crystal panel 110. [

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

120: Backlight unit
121: Optical sheet
125: reflector
129: LED assembly (129a: LED, 129b: PCB)
210: reflective polarizing film
The light guiding plate 221 includes a light guide plate 221b and a light incident surface 221b.
223: dot pattern
230: reverse prism condensing sheet (231: prism mountain)

Claims (6)

A reflector;
A light guide plate mounted on the reflection plate and having a dot pattern formed on an upper surface thereof;
An LED assembly arranged along the light incident surface of the light guide plate;
An optical sheet mounted on the light guide plate and including an inverse prism sheet condensing sheet;
And a liquid crystal panel
And the liquid crystal display device.
The method according to claim 1,
And a reflection polarizing film is positioned between the light incidence surface and the LED assembly.
3. The method of claim 2,
The reflective polarizing film may be a multilayer thin film structure in which a polarizer is embedded in a laminated structure of dielectric thin films having different refractive indexes or a wire grid reflective polarizing film including fine metal patterns arranged in parallel in one direction, .
The method according to claim 1,
The dot pattern is formed in a convex shape, a plurality of spaced apart and arranged, having a diameter of 10 to 500 μm, and a height of 1/2 ± 10 of the diameter of the liquid crystal display device
5. The method of claim 4,
Wherein the dot pattern is formed at a high density per unit area from the light-incident surface to the light-incident surface.
The method according to claim 1,
And the plurality of prism mountains are formed in a strip shape in which an obtuse angle and a valley are repeated along the longitudinal direction of the LED assembly.

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