KR102084394B1 - Polarizer and liquid crystal display device including the same - Google Patents

Abstract

The present invention relates to a polarizing plate and a liquid crystal display device including the same.
A liquid crystal display device according to the present invention includes a liquid crystal panel; A first polarizing plate and a second polarizing plate attached to the rear and front surfaces of the liquid crystal panel, respectively; And a backlight unit including at least one prism sheet positioned on the rear surface of the liquid crystal panel and a light source positioned on one side of the prism sheet, wherein the first polarizing plate includes a first polarizing film and the first polarizing film. The first and second support films are respectively located on one side and the other side of the second support film, and the second support film includes a plurality of polymer-based polymer beads.
Through this, it is possible to implement a liquid crystal display device that is lightweight, thin, and has high reliability and cost competitiveness.

Description

Polarizer and liquid crystal display device including the same {POLARIZER AND LIQUID CRYSTAL DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a polarizing plate and a liquid crystal display device including the same, and more particularly, to a polarizing plate having a haze characteristic and a liquid crystal display device including the same.

As the information society develops, the demand for display devices for displaying images is increasing in various forms, and in recent years, liquid crystal displays (LCDs), plasma display panels (PDPs), and organic light-emitting Various flat panel displays (FPDs) such as organic light emitting diodes (OLEDs) are used.

Among these flat panel display devices, the liquid crystal display device shows the principle of image implementation by optical anisotropy and polarization of the liquid crystal, and is advantageous for moving picture display and shows a feature with a large contrast ratio. , Monitors and mobile phones.

Such a liquid crystal display device (LCD) is an essential component of a liquid crystal panel interposed between two side-by-side substrates with a liquid crystal layer interposed therebetween, and light in a specific direction on the outer surface of each substrate. A polarizing plate passing through the bay is arranged, and the arrangement direction of the liquid crystal molecules is changed by an electric field in the liquid crystal panel to realize a difference in transmittance.

Here, since the liquid crystal panel does not have a light emitting element, a separate light source is required to display a difference in transmittance as an image, and for this purpose, a backlight unit having a light source is disposed on the rear surface of the liquid crystal panel.

Here, the backlight unit is classified into a direct type and an edge type according to the position of the light source. In the direct type backlight unit, the light emitted from the light source is directly disposed by placing the light source under the liquid crystal panel. A method of supplying to a liquid crystal panel, and a backlight unit of a side type method indirectly injects light emitted from a light source by using refraction and reflection in the light guide plate by arranging the light guide plate under the liquid crystal panel and placing the light source on at least one side of the light guide plate. It is a method of supplying to a liquid crystal panel.

The backlight unit includes a plurality of optical sheets including at least one diffusion sheet and at least two prism sheets to improve the luminance of light emitted from the light source.

Many of these optical sheets are disposed under the liquid crystal panel to provide high-intensity light to the liquid crystal panel.

On the other hand, recently, the liquid crystal display device has a wide display area as the use area of the portable computer as well as the desktop computer monitor and wall-mounted TV is diversified, and at the same time, research is actively conducted to realize a light and thin and relatively inexpensive liquid crystal display device. In progress, it is a situation that is hard to find a method for minimizing a large number of optical sheets among the components constituting the liquid crystal display device.

As one of these methods, a diffusion sheet may be omitted from among a plurality of optical sheets, which acts as a factor that degrades optical properties and lowers reliability of a liquid crystal display device.

In more detail, if a diffusion sheet for diffusing light is omitted, a rainbow phenomenon or a partially stained mura phenomenon may occur due to a prism sheet.

Accordingly, there is a need for a component capable of preventing a rainbow phenomenon or a mura phenomenon by replacing the role of a diffusion sheet among the components constituting the liquid crystal display device.

An object of the present invention for solving the above problems is to provide a polarizing plate having a haze treatment capable of eliminating a rainbow phenomenon or a mura phenomenon generated in a backlight unit and a liquid crystal display device including the same.

In addition, another object of the present invention is to provide a polarizing plate and a liquid crystal display device including the same that can simplify the manufacturing cost and process.

Through this, there is another object to realize a liquid crystal display device having light weight, thinness, and high reliability and price competitiveness.

A liquid crystal display device according to an embodiment of the present invention for achieving the above object, a liquid crystal panel; A first polarizing plate and a second polarizing plate attached to front and rear surfaces of the liquid crystal panel, respectively; And a backlight unit including at least one prism sheet positioned on a rear surface of the liquid crystal panel and a light source positioned on one side of the prism sheet, wherein the second polarizing plate includes a first polarizing film and the first polarizing film. It includes a first and a second support film which is located on one side and the other side of the second, the second support film is characterized in that it comprises a plurality of polymer-based polymer beads.

Here, the first polarizing plate is a second polarizing film, a third and fourth supporting films respectively located on one side and the other surface of the second polarizing film, and a hard coating layer located on the outermost surface while being the top of the fourth supporting film. It characterized in that it further comprises.

In addition, the fourth support film of the first polarizing plate includes a plurality of polymer-based polymer beads.

At this time, the polymer beads are characterized in that they have a refractive index in the range of 1.4 to 1.6 and a diameter in the range of 2 to 15 μm.

In particular, the bead amount included in the fourth support film is characterized in that it is smaller than the bead amount included in the second support film.

On the other hand, the second polarizing plate is characterized in that it further comprises a brightness enhancement film that is located on the back of the second support film and improves the brightness of light provided through the optical sheet of the backlight unit.

A polarizing plate according to an embodiment of the present invention includes a polarizing film; An upper support film positioned on the front surface of the polarizing film through which the incident light is emitted; It includes a lower support film located on the back surface of the polarizing film, the lower support film includes a large number of polymer-based polymer beads, the polymer beads have a refractive index in the range of 1.4 to 1.6, a diameter in the range of 2 to 15㎛ It is characterized by being in the form of a sphere with (毬).

It is characterized in that it further comprises a brightness enhancement film which is located on the rear surface of the lower support film and improves the brightness of light provided through the optical sheet of the backlight unit.

According to the present invention as described above, by applying a polarizing plate having a haze characteristic, it is possible to prevent a rainbow phenomenon or a mura phenomenon that may be generated by a prism sheet while reducing the number of optical sheets. Through this, it is possible to implement a liquid crystal display device having light weight, thinness, and reliable optical characteristics. In addition, the manufacturing cost of the entire liquid crystal display device is reduced by reducing the number of optical sheets to reduce component costs.

In addition, by including a polymer bead in the material of the support film included in the polarizing plate to form a support film having haze characteristics, a separate process for haze processing is not required, and the process can be simplified. At this time, a polymer bead is formed inside the polarizing plate to prevent interference with a prism sheet to be positioned below.

1 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a first embodiment of the present invention.
2 is a cross-sectional view showing a liquid crystal display device including a polarizing plate according to a comparative example.
3 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a second embodiment of the present invention.
4 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a third embodiment of the present invention.
5 is an exploded perspective view showing the liquid crystal display device according to FIG. 4 in more detail.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Here, the liquid crystal display device according to the present invention forms a pixel electrode and a common electrode on the same substrate and generates a horizontal electric field parallel to the substrate between the two electrodes so that the liquid crystal molecules move according to the horizontal electric field (in- It is preferable to use the plane switching (IPS) method.

1 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a liquid crystal display device including a polarizing plate according to a comparative example.

As shown in FIG. 1, the liquid crystal display device 100 includes a liquid crystal panel 110 displaying an image, a first polarizing plate 160 attached to one surface of the liquid crystal panel 110, and the other surface of the liquid crystal panel 110. It includes a second polarizing plate 170 attached to. At this time, each of the first polarizing plate 160 and the second polarizing plate 170 is attached to one surface and the other surface of the liquid crystal panel 110 by the first adhesive layer 182 and the second adhesive layer 184.

Here, the liquid crystal panel 110, although not shown in the drawing, is composed of a liquid crystal layer formed between the first and second substrates and the first and second substrates, and a pixel electrode and a common electrode on any one of the first and second substrates. Is formed. In one example, the pixel electrode and the common electrode may be formed on the first substrate positioned below. Therefore, the arrangement of the liquid crystal molecules of the liquid crystal layer is changed by an electric field generated between the two electrodes, and accordingly, the transmittance of light supplied from a backlight unit (not shown) located under the second polarizing plate 170 is adjusted.

The first polarizing plate 160 includes a first polarizing film 161, a first supporting film 163 and a second supporting film 165 and a surface layer 167 positioned on one surface and the other surface of the first polarizing film 161, respectively. ).

Here, the first polarizing film 161 may be formed of polyvinyl alcohol (PVA), which is prepared by drawing a polyvinyl alcohol film in one direction and adsorbing iodine (I) or dichroic dye. You can. At this time, the first polarizing film 161 has an absorption axis in the stretching direction and a transmission axis in a direction perpendicular to the absorption axis. Accordingly, the light incident on the first polarizing film 161 is linearly polarized with a component parallel to the transmission axis.

The first support film 163 and the second support film 165 may be formed of tri-acetyl cellulose (TAC).

The first support film 163 and the second support film 165 are for supporting the first polarizing film 161, respectively located on both sides of the first polarizing film 161 and the first polarizing film 161 It is desirable to have durability to maintain this mechanical strength and heat resistance and moisture resistance.

In addition, it is preferable that the first support film 163 and the second support film 165 have non-optical properties so that the light properties passing through the first polarizing film 161 are not changed.

The surface layer 167 is a layer located on the outermost surface where an image is implemented, and is also called a hard coating layer or an anti-reflection layer. It improves surface roughness and surface hardness and reduces external scattering of light incident from the outside. It plays a role in minimizing the whitening phenomenon that is blurred by the light source.

At this time, the surface layer 167 may have an antifouling function to prevent the first polarizing plate 160 from being contaminated by the surrounding environment.

The first polarizing plate 160 having such a structure is attached to a front surface of the liquid crystal panel 110, that is, a surface on which light is output. The first supporting film 163 adjacent to the liquid crystal panel 110, It is located in the order of the first polarizing film 161, the second support film 165, and the surface layer 167.

The second polarizing plate 170 includes a second polarizing film 171 and a third supporting film 173 and a fourth supporting film 175 positioned on one surface and the other surface of the second polarizing film 171, respectively.

 Here, the second polarizing film 171 may be formed of polyvinyl alcohol (PVA) like the first polarizing film 161, and the manufacturing method is also the same as that of the first polarizing film 161. In this case, the transmission axes of the first polarizing film 161 and the second polarizing film 171 may be arranged in parallel or orthogonal to each other, and more preferably, may be arranged to be orthogonal to each other.

The third support film 173 and the fourth support film 175 may be formed of tri-acetyl cellulose (TAC).

The third support film 173 and the fourth support film 175 are for supporting the second polarizing film 171, respectively located on both sides of the second polarizing film 171, the second polarizing film 171 It is desirable to have durability to maintain this mechanical strength and heat resistance and moisture resistance.

At this time, the fourth support film 175 is characterized in that it contains a plurality of polymer-based polymer beads 176 therein to be haze-treated.

Here, the polymer beads 176 have a refractive index in the range of 1.4 to 1.6, and are contained in the fourth support film 175 in a spherical shape having a diameter in the range of 2 to 15 μm. At this time, the polymer beads 176 may be contained up to about 1 to 80%.

Accordingly, light incident on the fourth support film 175 is diffused and scattered (scattered) by the fourth support film 175.

The fourth support film 175 complements the optical characteristics of the substrate to be positioned at the bottom of the second polarizing plate 170, and also prevents interference with the substrate to be positioned at the bottom.

In more detail, the prism sheet of the backlight unit may be positioned under the second polarizing plate 170 because light is dispersed through a plurality of beads 176 contained in the fourth support film 175. The rainbow phenomenon or mura phenomenon, which may be generated by the prism sheet, can be prevented.

In addition, the fourth support film 175 includes a plurality of beads 176 therein to prevent the beads 176 from being exposed and to have a flat surface, thereby forming a prism sheet to be located under the second polarizing plate 170. There is an advantage that it is possible to simplify the manufacturing process of the polarizing plate at the same time as to prevent the occurrence of a crack on the surface. This will be described in more detail later.

The second polarizing plate 170 is attached to the rear surface of the liquid crystal panel 110 and is a component positioned between the liquid crystal panel 110 and the backlight unit (not shown), and the third supporting film adjacent to the liquid crystal panel 110 ( 173), the second polarizing film 171 and the fourth support film (175).

On the other hand, in the case of the third support film 173, it is preferable to haze only the fourth support film 176 because light leakage may occur when beads are added. Since the third support film 173 is located on the inner surface (top) of the second polarizing film 171, when beads are added (haze treatment) to the third support film 173, the second polarizing film 171 This is because the polarized state can be changed by the bead inside, as the light polarized by passes through the third support film 173. This can cause light leakage. Therefore, it is preferable that the third support film 173 has a non-optical property so that the light property passing through the second polarizing film 171 is not changed.

The first adhesive layer 182 is located between the first polarizing plate 160 and the liquid crystal panel 110, and the second adhesive layer 184 is located between the second polarizing plate 170 and the liquid crystal panel 110. , Each of the first adhesive layer 182 and the second adhesive layer 184 may be provided on one surface of the first polarizing plate 160 and the second polarizing plate 170.

The first and second adhesive layers 182 and 184 may be pressure sensitive adhesive (PSA).

Hereinafter, the polarizing plate according to the first embodiment of the present invention described above is compared with the polarizing plate according to the comparative example. Here, the structure except for the structure of the second polarizing plate in the liquid crystal display device according to the comparative example is the same as the first embodiment of the present invention, so a detailed description thereof will be omitted.

As shown in FIG. 2, the liquid crystal display device 1 according to the comparative example includes a liquid crystal panel 10 displaying an image, a first polarizing plate 60 attached to one surface of the liquid crystal panel 10, and a liquid crystal panel ( It includes a second polarizing plate 70 attached to the other surface of 10). At this time, each of the first polarizing plate 60 and the second polarizing plate 70 is attached to one surface and the other surface of the liquid crystal panel 10 by the first adhesive layer 82 and the second adhesive layer 84.

Here, the second polarizing plate 70 is formed on the lower portions of the upper and lower supporting films 73 and 75, and the lower supporting films 75, which are located on one surface and the other surface of the polarizing film 71 and the polarizing film 71, respectively. The scattering layer 77 is included.

The second polarizing plate 70 is attached to the rear surface of the liquid crystal panel 10 and is located between the liquid crystal panel 10 and the backlight unit (not shown), and adjacent to the liquid crystal panel 10, the upper support film 73, The polarizing film 71, the lower support film 75 and the scattering layer 77 are positioned in this order.

At this time, the scattering layer 77 is for haze treatment, and is formed by coating a plurality of beads 76, for example, silica on the back surface of the lower support film 75, and the surface of the uneven surface by the plurality of beads 76 It is formed.

As described above, the light entering the second polarizing plate 70 is scattered by the scattering layer 77 so that the degree of unevenness through the plurality of beads 76, that is, the surface roughness indicating the surface roughness, has a certain value. Diffusion and dispersion.

Through this, a rainbow phenomenon or a mura phenomenon, which may be generated by a prism sheet to be located under the second polarizing plate 170, can be prevented.

However, since the scattering layer 77 is located on the outermost surface and is exposed to the outside, there is a problem in that interference with a prism sheet to be located under the second polarizing plate 70 occurs. That is, a plurality of beads 76 partially exposed through the surface of the scattering layer 77 due to vibration such as impact contact the surface of the prism sheet, and a prism sheet is cracked.

In addition, since the scattering layer 77 has to be formed by performing a coating process on the back surface of the lower support film 75, it increases the number of processes and acts as a factor to increase the thickness of the entire polarizing plate.

On the other hand, since the second polarizing plate 170 according to the first embodiment of the present invention is formed by including a large number of polymer beads 176 in the material when forming the fourth support film 175, the scattering layer (77) of the comparative example ) Does not require a separate coating process and has the advantage of simplifying the process.

In addition, by including the polymer beads 176 in the fourth support film 175 without separately forming the scattering layer 77 for haze treatment, there is an advantage that the overall thickness of the second polarizing plate 170 becomes slimmer.

In addition, as the most important object of the present invention, a rainbow phenomenon or a mura phenomenon that may be generated by a prism sheet to be located under the second polarizing plate 170 is prevented, and there is an advantage of avoiding interference with the prism sheet.

Meanwhile, the polymer beads for haze treatment may be included in the first polarizing plate as well as the second polarizing plate.

3 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a second embodiment of the present invention. Here, since the structures except the structures of the supporting films of the first polarizing plate and the second polarizing plate are the same as in FIG. 1, the same reference numerals are given to the same components, and detailed description thereof will be omitted.

As illustrated in FIG. 3, the liquid crystal display 200 includes a liquid crystal panel 110 displaying an image, a first polarizing plate 260 attached to one surface of the liquid crystal panel 110, and the other surface of the liquid crystal panel 110. It includes a second polarizing plate 270 attached to. At this time, each of the first polarizing plate 260 and the second polarizing plate 270 is attached to one surface and the other surface of the liquid crystal panel 110 by the first adhesive layer 182 and the second adhesive layer 184.

Here, the first polarizing plate 260 is a first polarizing film 161, the first supporting film 163 and the second supporting film 265 and the surface layer located on one surface and the other surface of the first polarizing film 161, respectively (167).

The first polarizing plate 260 is attached to a front surface of the liquid crystal panel 110, that is, a surface on which light is output, and adjacent to the liquid crystal panel 110, the first supporting film 163, the first The polarizing film 161, the second support film 265, and the surface layer 167 are positioned in this order.

Meanwhile, the second polarizing plate 270 includes a second polarizing film 171 and a third supporting film 173 and a fourth supporting film 275 positioned on one surface and the other surface of the second polarizing film 171, respectively. do.

The second polarizing plate 270 is a component that is attached to the rear surface of the liquid crystal panel 110 and positioned between the liquid crystal panel 110 and the backlight unit (not shown). The third supporting film 173 is adjacent to the liquid crystal panel. It is located in the order of the second polarizing film 171 and the fourth supporting film 275.

Here, the second support film 265 of the first polarizing plate 260 and the fourth support film 275 of the second polarizing plate 270 contain a plurality of polymer-based polymer beads 266 and 276 therein to haze treatment. It is characteristic.

The polymer beads 276 and 277 have a refractive index in the range of 1.4 to 1.6, and a spherical shape having a diameter in the range of 2 to 15 μm.

At this time, the first bead amount of the polymer beads contained in the second supporting film 265 of the first polarizing plate 260 is the polymer beads contained in the fourth supporting film 275 of the second polarizing plate 270 Should be less than the second bead amount.

This is because the first polarizing plate 260 is located on the front surface of the liquid crystal panel 110 and is directly related to the contrast ratio. To further explain this, light is emitted through the first polarizing plate 260. If too much polymer beads 266 are included in the second supporting film 265 of the first polarizing plate 260, the light is scattered too much. Dispersion occurs and the contrast ratio is lowered. Accordingly, as an example, when the amount of the first bead contained in the fourth support film 275 is 40%, the amount of the second bead contained in the second support film 265 is preferably 10%. As another example, the diameter of the bead contained in the second support film 265 may be reduced, or the diameter of the bead may be reduced, and the amount of the first bead contained in the fourth support film 275 may be the second support film. It may be made smaller than the amount of the second bead contained in (265).

Meanwhile, in the case of the first and third supporting films 163 and 173, it is preferable to haze only the second and fourth supporting films 265 and 275 because light leakage may occur when beads are added. In more detail, the first support film 163 is located on the inner surface (bottom) of the first polarizing film 161. If beads are added to the first support film 163, the display panel 120 This is because light having a specific polarization state by the liquid crystal molecules passes through the first support film 163 and the polarization state may be changed by beads inside. Since this may cause light leakage, it is preferable that the first support film 163 is not provided with optical characteristics (Haser treatment) to maintain the polarization state. In the case of the third support film 173, it has been already described above, and thus is omitted.

Meanwhile, in order to further improve the optical characteristics of the liquid crystal display device, the second polarizing plate may further include a luminance enhancement film.

4 is a cross-sectional view schematically showing a liquid crystal display device including a polarizing plate according to a third embodiment of the present invention. Here, since the structure except the second polarizing plate further including the luminance enhancement film is the same as in FIG. 3, the same reference numerals are given to the same components and detailed description thereof will be omitted.

As shown in FIG. 4, the liquid crystal display device 300 includes a liquid crystal panel 110 displaying an image, a first polarizing plate 260 attached to one surface of the liquid crystal panel 110, and a liquid crystal panel 110. And a second polarizing plate 370 attached to the other surface. At this time, each of the first polarizing plate 260 and the second polarizing plate 370 is attached to one surface and the other surface of the liquid crystal panel 110 by the first adhesive layer 182 and the second adhesive layer 184.

Here, the second polarizing plate 370 includes a second polarizing film 171, a third supporting film 173 and a fourth supporting film 275 located on one surface and the other surface of the second polarizing film 171, and And a luminance enhancement film 310 positioned on the back surface of the fourth support film 275 through the third adhesive layer 312.

The luminance enhancement film 310 serves to provide a high-brightness light to the liquid crystal panel 110 by further improving the luminance of the backlight unit disposed on the rear surface of the liquid crystal panel 110, and dual brightness enhancement film film: DBEF).

The luminance enhancement film 310 is integrated into the second polarizing plate 370 through the third adhesive layer 312.

At this time, the third adhesive layer 312 may be a pressure sensitive adhesive (PSA), and is provided on one surface of the brightness enhancing film 310 in the state of the fourth supporting film 275 of the second polarizing plate 370. It can be attached to the back.

On the other hand, instead of or in addition to the above-mentioned brightness enhancement film 310, a protective film for protecting the rear surface of the second polarizing plate 370 and preventing interference with a sheet to be positioned below may be provided.

On the other hand, the second polarizing plate (170 in FIG. 1) according to the first embodiment of the present invention may also further include a luminance enhancement film.

FIG. 5 is an exploded perspective view showing the liquid crystal display device according to FIG. 4 in more detail, and refer to FIG. 4.

As shown in FIG. 5, the liquid crystal display 300 includes a liquid crystal panel 110 and a backlight unit 120. At this time, although not shown, it may further include a support main 130 and a top cover 140 and a cover bottom 150 for modularizing the liquid crystal panel 110 and the backlight unit 120.

Here, the liquid crystal panel 110 is a part that plays a key role in image display, and is composed of first and second substrates 112 and 114 bonded to each other with a liquid crystal layer interposed therebetween.

Here, although not shown in the drawing, a pixel is defined by a plurality of gate lines and data lines intersecting on the inner surface of the first substrate 112, which is usually called a lower substrate or an array substrate, under the premise of an active matrix method. A thin film transistor (TFT) is provided to be connected one-to-one to a transparent pixel electrode formed in each pixel. At this time, a transparent common electrode is formed on the same layer or a different layer from the transparent pixel electrode.

In addition, as an example corresponding to each pixel on the inner surface of the second substrate 114 called the upper substrate or the color substrate, color filters of red (R), green (G), and blue (B) colors, and these A black matrix is formed around each of the non-display elements such as a gate line, a data line, and a thin film transistor.

In addition, a second polarizing plate 370 that selectively transmits only specific light is attached to the outer surface of the first substrate 112, and a first that selectively transmits only specific light to the outer surface of the second substrate 114. The polarizing plate 260 is attached. At this time, the second polarizing plate 370 may further include a brightness enhancing film (310 in FIG. 4).

Here, each of the first and second polarizing plates 260 and 370 includes a plurality of polymer-based polymer beads (266 and 276 in FIG. 4) inside the second and fourth support films (265 and 275 in FIG. 4). It is characterized in that the haze treatment.

The first and second polarizing plates 260 and 370 are diffusely scattered (scattered) in which light incident by the polymer beads (266 and 276 in FIG. 4) is diffused and dispersed.

By the luminance enhancement film (310 of FIG. 4) provided in the haze-treated first and second polarizing plates 260 and 370 and the second polarizing plate 370, the entire optical sheet provided in the backlight unit 120 Despite reducing the number, it is possible to further improve the optical characteristics (high brightness).

The printed circuit board 117 is connected through at least one edge of the liquid crystal panel 110 through a connecting member (not shown) such as a flexible circuit board or a tape carrier package (TCP). At this time, the printed circuit board 117 may be properly folded to the side of the support main (not shown) or the back of the cover bottom (not shown) during the modularization process.

Accordingly, the liquid crystal panel 110 having the above-described structure, when the thin film transistor selected for each gate line is turned on by the on or off signal of the gate driving circuit transmitted through the printed circuit board 117, signals of the data driving circuit. The voltage is transferred to the corresponding pixel electrode through the data line, and accordingly, the arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, thereby indicating a difference in transmittance.

On the rear surface of the liquid crystal panel 110, a backlight unit 120 is provided to supply light to display a difference in transmittance as an image.

The backlight unit 120 includes a light source disposed along one edge of the support main 130 or one inner surface of the cover bottom 150, a reflector 125, and a light guide plate 123 mounted on the reflector 125 And it includes an optical sheet 121 interposed thereon.

The LED 129a is used as the light source, and each of the plurality of LEDs 129a is spaced apart at regular intervals to be mounted on the LED Printed Circuit Board (PCB) 129b to form the LED assembly 129.

At this time, the LED printed circuit board 129b may correspond to a metal core printed circuit board (MCPCB) having a heat dissipation function for dissipating heat generated from a plurality of LEDs 129a.

The position of the LED assembly 129 is fixed by a method such as adhesion so that light emitted from the plurality of LEDs 129a faces the light incident portion of the light guide plate 123.

Accordingly, light emitted from the plurality of LEDs 129a of the LED assembly 129 enters the light guide plate 123 and is supplied to the liquid crystal panel 110 using refraction and reflection in the light guide plate 123.

Here, the LED housing 129 may be provided with an LED housing (not shown) for more efficiently dissipating heat generated from each of the plurality of LEDs 129a.

At this time, the LED housing (not shown) is made of a metal material having excellent thermal conductivity, located between the LED assembly 129 and the cover bottom 150, and the back of the LED printed circuit board 129b and a number of LEDs 129a. It can be composed of a vertically curved b-shaped to wrap.

The reflector 125 improves the luminance of light by reflecting light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 in the shape of a square plate.

The light guide plate 123 guides the light emitted from each of the plurality of LEDs 129a to realize a higher quality surface light source.

The light guide plate 123 may have a square plate shape, and may include a pattern having a specific shape on the back surface to supply a uniform surface light source.

At this time, the pattern may be variously configured such as an elliptical pattern, a polygonal pattern, a hologram pattern, etc. to guide the light incident into the light guide plate 123. Is formed on the lower surface of the light guide plate 123 by a printing method or an injection method.

The light guide plate 123 for this can be made of polymethyl methacrylate (PMMA) or polymethacrylstyrene (MS) resin in which polymethyl methacrylate (PMMA) and polystyren (PS) are mixed. have.

The optical sheet 121 interposed on the upper portion of the light guide plate 123 may be a prism sheet that collects light converted into a surface light source by the light guide plate 123 and allows a more uniform surface light source to enter the liquid crystal panel 110. .

Here, the liquid crystal display device according to the present invention is characterized in that the diffusion sheet for diffusing light is omitted.

On the other hand, although one optical sheet 121 is shown, at least two prism sheets in which the longitudinal directions of the optical patterns cross each other or are arranged side by side may be provided.

At this time, as described above, the polymer-based polymer beads (266, 276 in FIG. 4) are included in the second and fourth support films (265, 275 in FIG. 4) of the first and second polarizing plates 260 and 370, respectively. As a result, as the diffusion sheet is omitted, a rainbow phenomenon or a mura phenomenon that may be generated by the prism sheet 121 can be prevented.

Light emitted from the LED assembly 129 of the backlight unit 120 in the liquid crystal display device 300 having such a structure enters the light guide plate 123 through the light incident portion of the light guide plate 123, and thereafter, a liquid crystal panel therein. It is refracted toward 110 and is processed into a more uniform high-quality surface light source while passing through the optical sheet 160 together with the light reflected by the reflector 125 to be supplied to the liquid crystal panel 110.

As described above, the liquid crystal display device according to the present invention hazes the second and fourth supporting films (265 and 275 of FIG. 4) of the first and second polarizing plates 260 and 370 while reducing the number of optical sheets. By supplementing the optical characteristics due to the omission of the optical sheet (diffusion sheet), it has high reliability and is characterized by being implemented in light weight and thin form. In particular, there is an advantage in that the cost can be minimized by including a polymer bead in a material forming a support film without adding a separate process.

On the other hand, in the above, a liquid crystal display device having a side-type backlight unit in which the LED assembly is disposed to face at least one edge of the light guide plate is described as an example, but the present invention is not limited thereto. It can also be applied to a liquid crystal display device to which a direct type backlight unit is applied. In this case, the light guide plate may be omitted, and a diffusion plate and an optical sheet positioned at a predetermined distance apart from the top of the reflector may be disposed.

The embodiments of the present invention as described above are only exemplary, and a person having ordinary knowledge in the technical field to which the present invention pertains can freely deform without departing from the gist of the present invention. Accordingly, the protection scope of the present invention includes the appended claims and variations of the present invention within the scope equivalent thereto.

100, 200, 300: liquid crystal display 110: liquid crystal panel
160, 260: first polarizing plate 161: first polarizing film
163: 1st support film 165, 265: 2nd support film
166: polymer beads 167: hard coating layer
170, 270, 370: second polarizing plate 171: second polarizing film
173: 3rd support film 175, 275: 4th support film
176: polymer beads 310: luminance enhancement film

Claims (10)

A liquid crystal panel;
A light source that supplies light to the liquid crystal panel;
A prism sheet disposed on the rear surface of the liquid crystal panel to output light supplied from a light source to the liquid crystal panel; attached to the front surface of the liquid crystal panel, the first polarizing film, and the rear and front surfaces of the first polarizing film, respectively A first polarizing plate composed of a first supporting film and a second supporting film; And
Attached to the rear surface of the liquid crystal panel, a second polarizing film, a third supporting film disposed on the front surface of the second polarizing film, and a fourth supporting film disposed on the rear surface of the second polarizing film and directly facing the prism sheet It consists of a second polarizing plate made of,
A plurality of first polymer beads are included only in the second support film excluding the first support film of the first polarizing plate, and a plurality of second polymer beads are included only in the fourth support film excluding the third support film,
The amount of first polymer beads included in the second support film is less than the amount of second polymer beads included in the fourth support film.
According to claim 1,
The first polarizing plate further comprises a hard coating layer disposed on the second polarizing film.
delete According to claim 1,
The first and second polymer beads have a refractive index in the range of 1.4 to 1.6, a liquid crystal display device, characterized in that the spherical (형태) having a diameter in the range of 2 to 15㎛.
delete According to claim 1,
The second polarizing plate is disposed on the rear surface of the fourth support film, the liquid crystal display device further comprises a brightness enhancement film for improving the brightness of the light outputting the prism sheet.
delete delete The liquid crystal display device of claim 1, further comprising a light guide plate disposed under the prism sheet to supply light output from a light source to the prism sheet. The liquid crystal display device according to claim 1, wherein the plurality of polymer beads are included in a fourth protective film to planarize the rear surface of the fourth protective film.

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