KR102078025B1 - Optical sheet and liquid crystal display device having the same - Google Patents

Abstract

The present invention relates to an optical sheet and a liquid crystal display device including the same.
A liquid crystal display device according to the present invention includes a backlight unit including a liquid crystal panel, an optical sheet positioned on a rear surface of the liquid crystal panel, and a light source positioned on one side of the optical sheet, wherein the optical sheet includes: a base layer; A first refractive index formed under the base layer and having a first refractive index, a low refractive index layer covering the first optical pattern and having a second refractive index, and a third refractive index formed on the base layer; The branch includes a second optical pattern.
Through this, it is possible to implement a liquid crystal display device which is advantageous in terms of weight, thinness and price.

Description

Optical sheet and liquid crystal display including the same {OPTICAL SHEET AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

The present invention relates to an optical sheet and a liquid crystal display including the same, and more particularly, to an optical sheet and a liquid crystal display including the same, which can reduce the total number of sheets and contribute to slimming.

In line with the recent information age, the display field has also been rapidly developed, and as a display device having the advantages of thinning, light weight, and low power consumption, a liquid crystal display device (LCD) and organic light emitting diodes are used. BACKGROUND ART Organic light emitting diode (OLED) displays have excellent performance and are widely used.

Here, liquid crystal display devices (LCDs), which are advantageous for moving image display and have a large contrast ratio, are actively used in TVs, monitors, and mobile phones, are characterized by optical anisotropy and polarization of liquid crystals. The principle of image realization by polarization is shown.

Such a liquid crystal display is an essential component of a liquid crystal panel, which is bonded between two substrates in parallel with a liquid crystal layer, and realizes a difference in transmittance by changing an arrangement direction of liquid crystal molecules with an electric field in the liquid crystal panel. do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight unit having a light source is disposed on the back 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. The direct type backlight unit directly arranges the light emitted from the light source by arranging the light source under the liquid crystal panel. The backlight unit of the side-type backlight unit is configured to arrange the light guide plate under the liquid crystal panel, and to arrange the light source on at least one side of the light guide plate to indirectly emit light emitted from the light source by using the refraction and reflection of the light guide plate. In this way, the liquid crystal panel is supplied.

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

On the other hand, the liquid crystal display device has recently been actively researched to realize a lightweight, thin and relatively inexpensive liquid crystal display device as well as to have a wide display area as the use area of the portable computer, desktop computer monitor and wall-mounted television is diversified. In progress, the situation is to find a way to minimize the plurality of optical sheets of the components constituting the liquid crystal display device.

As one of these methods, some of the plurality of optical sheets may be omitted, which acts as a factor of deteriorating optical characteristics and lowers the reliability of the entire LCD.

Alternatively, the two prism sheets may be used by bonding or adhering to each other, which has a problem that the effect of the thickness is too small and the effect is insufficient.

In another method, the thickness of the support layer of each optical sheet is reduced to reduce the thickness of the entire optical sheet. In this case, when the thickness of the support layer is reduced, wrinkles are generated in the sheet during the reliability test of high temperature and humidity, and the optical characteristics are remarkably reduced. There is a problem of lowering and furthermore becoming a defective product.

An object of the present invention for solving the above problems is to provide an optical sheet and a liquid crystal display including the same to have an optical characteristic corresponding to at least two optical sheets as one optical sheet.

Through this, there is another object to implement a liquid crystal display device that is lightweight and thin and relatively inexpensive.

Liquid crystal display device according to the present invention for achieving the above object is a liquid crystal panel; And a backlight unit including an optical sheet positioned on a rear surface of the liquid crystal panel and a light source positioned on one side of the optical sheet, wherein the optical sheet is formed on a base layer and a lower portion of the base layer. The branch includes a first optical pattern, a low refractive layer covering the first optical pattern and having a second refractive index, and a second optical pattern formed on the base layer and having a third refractive index.

The first optical pattern may be a plurality of inverse prism patterns, and the second optical pattern may be one of a plurality of prism patterns including an acid and a plurality of semicircle patterns including curved surfaces.

At this time, the second optical pattern is characterized in that it has a wavy shape along the longitudinal direction.

The first refractive index is the same as the third refractive index, or less than the third refractive index, the second refractive index is characterized in that larger than the refractive index of the air and smaller than the first and third refractive index.

The first pitch of the first optical pattern and the second pitch of the second optical pattern are different from each other.

Further, the first angle of the mountain of the first optical pattern is smaller than the second angle of the mountain of the second optical pattern.

The low refractive layer is formed to have the same first thickness on the same layer as the first optical pattern.

Alternatively, the low refractive layer has a second thickness that is thicker than the first optical pattern, and the bottom surface of the low refractive layer is characterized in that the concave-convex pattern including concave and convex portions rounded.

Unlike this, it is characterized in that it comprises a bead layer formed by coating a plurality of beads on the back of the low refractive index layer, and a bottom layer covering a plurality of beads under the bead layer to have a flat surface.

The second optical pattern is characterized in that it comprises a urethane-based elastic additive.

On the other hand, the optical sheet according to the present invention, the base layer; A first optical pattern formed under the base layer and having a first refractive index; A low refractive layer covering the first optical pattern and having a second refractive index; And a second optical pattern formed on the base layer and having a third refractive index, wherein the first optical pattern is a plurality of inverse prism patterns, and the second optical pattern is a plurality of prism patterns including acid; Characterized in that it is one of a plurality of semicircle patterns including a curved surface.

As described above, according to the present invention, the optical patterns having different patterns are formed on the upper and lower portions of the base layer, respectively, so that each of the optical patterns can function as an optical sheet using the base layer in common.

In addition, by including a low refractive layer covering the lower optical pattern to prevent the pattern from being exposed to the outside, it is possible to increase the light efficiency by reducing the light reflection amount of the incident light. In addition, the bead is coated on the low refractive index layer, or the concave-convex pattern is formed on the rear surface of the low refractive layer, thereby increasing the optical efficiency.

Through this, there is an advantage having the same optical characteristics as using at least two sheets of the conventional optical sheet as one optical sheet.

In addition, as the base layer is commonly used, component cost is reduced, and further, manufacturing cost of the entire liquid crystal display device is reduced, and a lightweight and thin liquid crystal display device can be realized.

1 is a cross-sectional view showing an optical sheet according to a first embodiment of the present invention.
2 is an exploded perspective view showing the optical sheet of FIG.
3 is an exploded perspective view showing another example of the optical sheet according to the first embodiment of the present invention.
4 is a cross-sectional view showing another example of the optical sheet according to the first embodiment of the present invention.
5 is a cross-sectional view showing an optical sheet according to a second embodiment of the present invention.
6 is a sectional view showing an optical sheet according to a third embodiment of the present invention.
7 is an exploded perspective view showing a liquid crystal display device including the optical sheet according to the first embodiment of the present invention.

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

1 is a cross-sectional view showing an optical sheet according to a first embodiment of the present invention, Figure 2 is an exploded perspective view showing the optical sheet of FIG.

As illustrated, the optical sheet 160 has a first optical pattern 163, a low refractive index layer 165, and an upper portion of the base layer 161 formed under the base layer 161 based on the base layer 161. It includes a second optical pattern 169 formed in.

The base layer 161 is most preferably made of polyethylene terephthalate (PET), but is not limited thereto. Polyethersulphone (PES), polyacrylate (PAR), polyetherimide (polyetherimide) PEI), polyethylene napthalate (PEN), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC) or cellulose triacetate (TAC), Or cellulose acetate propionate (CAP).

The first optical pattern 163 is formed of a plurality of inverse prism patterns formed to protrude from the base layer 161 toward the rear direction.

Here, the first optical pattern 163 is a mountain formed by the plurality of first and second inclined surfaces 163a and 163b which are symmetrical to each other, and the plurality of first and second inclined surfaces 163a and 163b alternate with each other. 164a and valley 164b.

Accordingly, the peak 164a and the valley 164b are repeated along the first direction, which is the longitudinal direction of the base layer 161, and the peak 164a and the valley 164b are formed in the first optical pattern 163. And extending in a second direction perpendicular to the one direction.

In this case, each of the first optical patterns 163 is formed of a first pitch P1 having a range of 30 μm to 60 μm, and the peaks 164a of each of the first optical patterns 163 are 44 degrees to 77 degrees. It may be formed at a first angle θ1 having a range of degrees.

The first optical pattern 163 has a first refractive index, which includes a range of 1.46 to 1.58.

The low refractive layer 165 formed under the first optical pattern 163 covers the first optical pattern 163 by filling the valleys 164b between neighboring patterns in the first optical pattern 163 and smoothes the first optical pattern 163. To form a (flat) surface. Accordingly, the low refractive layer 165 is formed on the same layer as the first optical pattern 163.

In this case, the low refractive layer 165 may be formed on the same layer as the first optical pattern 163 with the same first thickness H1 or may be completely covered by the first optical pattern 163 although not shown in the drawing. It may be formed to a second thickness thicker than the thickness (H1).

In addition, the low refractive index layer 165 has a second refractive index within the range of 1.38 to 1.46, which is larger than the optical refractive index of air and is the lowest refractive index among the constituent layers constituting the optical sheet 160.

The low refractive layer 165 prevents the first optical pattern 163 from being exposed to the outside so as not to be damaged by interference with other substrates, and also reduces the amount of light reflection of the light incident through the rear surface and minimizes light loss. Play a role.

Although not shown in the drawings, a lower layer (not shown) may be further included below the low refractive layer 165 to improve adhesion with a substrate to be positioned below the optical sheet 160. Not shown) may have the same refractive index as the low refractive layer 165.

The second optical pattern 169 is formed of a plurality of prism patterns formed to protrude from the base layer 161 toward the front direction.

Here, the second optical pattern 169 includes a plurality of first and second inclined surfaces 169a and 169b which are symmetrical to each other, and a plurality of first and second inclined surfaces 169a and 169b which are alternately formed to meet each other. 168a and the valley 168b.

The second optical pattern 169 repeats the peaks 168a and the valleys 168b along the first direction, and extends in the second direction where the peaks 168a and the valleys 168b vertically cross the first direction. It is done.

In this case, each of the second optical patterns 169 is formed of a second pitch P2 having a range of 20 μm to 60 μm, and the peaks 169a of each of the second optical patterns 169 are 75 degrees to 105 degrees. It may be formed at a second angle θ2 having a range of degrees. Here, although the first optical pattern 163 and the second optical pattern 169 may be formed to have the same angle as shown in the drawing, the second angle θ2 is the first optical pattern 163. It may be formed at an angle larger than each first angle θ1. In this case, the light collected through the first optical pattern 163 and diffused through the second optical pattern 163 may further improve luminance.

On the other hand, the second optical pattern 169 is formed of a prism pattern including an acid such as triangular prism, pyramid, cone, or curved surface such as lens and semi-circle column. It may be formed in a semicircle pattern including. In this case, when the second optical pattern 169 is formed as a semicircle pattern, the light may be collected through the first optical pattern 163 and may be diffused through the second optical pattern 169.

Further, the peaks 168a and the valleys 168a of each of the second optical patterns 169 may be curved in the horizontal direction with respect to the pattern surface, or the peaks 168a and the valleys of the second optical patterns 169 may be curved. 168a) may have bending in the vertical direction as well as bending in the horizontal direction with respect to the pattern surface. That is, the peaks 168a and valleys 168a have a continuous wave shape along the length direction, and the continuous wave shape may have a step with respect to the pattern surface. Through this, moiré, which is an interference fringe phenomenon, may be prevented and luminance may be improved by providing a scattering effect.

The second optical pattern 169 may have a third refractive index, and the third refractive index may range from 1.55 to 1.65. The third refractive index may have a value equal to or greater than the first refractive index of the first optical pattern 163.

In addition, the second optical pattern 169 may include an elastic additive, for example, urethane, to protect the acid 168a. Through this, the second optical pattern 169 is easily damaged by contact with other components disposed above the optical sheet 160 or by external shocks and can be restored to its original state, thereby facilitating handling. There is an advantage.

Each of the first optical pattern 163, the low refractive layer 165, and the second optical pattern 169 may include any one of urethane acrylate, epoxy acrylate, polyester acrylate, and acrylic polymer as a main component. have.

Meanwhile, although the first pitch P1 of the first optical pattern 163 and the second pitch P2 of the second optical pattern 169 are illustrated as being identical to each other in the drawing, they may be formed differently. In this case, when the pitches are different from each other, the moiré, which is an interference fringe phenomenon that may be generated by overlapping the first optical pattern 163 and the second optical pattern 169, may be more easily prevented.

In the optical sheet 160 according to the first embodiment of the present invention having such a structure, each of the first optical pattern 163 and the second optical pattern 169 uses a base layer 161 in common. It is characterized by acting as.

That is, one optical sheet according to the present invention has the same optical characteristics as at least two optical sheets on which a prism pattern is formed.

On the other hand, it has been described above that the longitudinal directions of the first optical pattern and the second optical pattern are the same, but may be formed to cross each other. In addition, a start position of the first optical pattern and the second optical pattern may be different from each other.

This will be described with reference to the drawings.

3 is an exploded perspective view showing another example of the optical sheet according to the first embodiment of the present invention, Figure 4 is a cross-sectional view showing another example of the optical sheet according to the first embodiment of the present invention. Here, since the basic structure is the same as that of FIG.

As shown in FIG. 3, the first optical pattern 162 has a peak and valley repeating along a second direction perpendicular to the longitudinal direction of the base layer 161, and the peak and valley cross each other perpendicularly to the second direction. It may be made extending in one direction.

Accordingly, the length direction of the first optical pattern 162 crosses the length direction of the second optical pattern 169.

Meanwhile, as illustrated in FIG. 4, overlapping between patterns may be prevented by different starting positions of the first optical pattern 163 and the second optical pattern 167. As a result, it is possible to prevent moiré, which is an interference fringe phenomenon that may occur when the first optical pattern 163 and the second optical pattern 167 overlap each other.

In this case, although the first optical pattern 163 is shown as the valley 164b starts first and the second optical pattern 167 starts the mountain 168a first, the present invention is not limited thereto and vice versa. Do.

On the other hand, another material may be added to the low refractive layer, or the shape may be modified to change the optical properties of the optical sheet.

This will be described in more detail with reference to the drawings.

5 is a cross-sectional view showing an optical sheet according to a second embodiment of the present invention, Figure 6 is a cross-sectional view showing an optical sheet according to a third embodiment of the present invention. Here, since the structure except for the low refractive index layer and the bead layer is the same as in FIG. 1, the same reference numerals are assigned to the same components, and detailed description thereof will be omitted.

First, as shown in FIG. 5, the optical sheet 260 according to the second exemplary embodiment of the present invention has a first optical pattern 163 formed at a lower portion of the base layer 161 with respect to the base layer 161. The refractive layer 265 and the second optical pattern 169 formed on the base layer 161 are included.

Here, the low refractive layer 265 covers the first optical pattern 163 and is formed to have a second thickness H2 thicker than the first optical pattern 163.

The low refractive index layer 265 has a second refractive index within the range of 1.38 to 1.46, where the second refractive index is larger than the optical refractive index of air and is the lowest refractive index among the constituent layers constituting the optical sheet 260.

By having a low second refractive index as described above, the low refractive layer 265 serves to reduce light reflection of light incident through the rear surface and minimize light loss.

In addition, a concave-convex pattern 266 in which the concave portion 266a and the convex portion 266b are repeated is formed on the rear surface of the low refractive layer 265. The concave portion 266a and the convex portion 266b of the concave-convex pattern 266 Is characterized in that the rounded process.

The uneven pattern 266 serves to improve the brightness by scattering incident light.

Next, as shown in FIG. 6, the optical sheet 360 according to the third exemplary embodiment of the present invention has a first optical pattern 163 sequentially formed below the base layer 161 based on the base layer 161. ), A low refractive layer 365, a bead layer 266 and a back layer 370, and a second optical pattern 169 formed on the base layer 161.

Here, the low refractive layer 365 covers the first optical pattern 163 and is formed to have a second thickness H2 thicker than the first optical pattern 163.

The low refractive index layer 365 has a second refractive index within the range of 1.38 to 1.46, where the second refractive index is larger than the optical refractive index of air and is the lowest refractive index among the constituent layers constituting the optical sheet 360.

By having the second refractive index as described above, the low refractive index layer 365 serves to reduce the light reflection amount of the light incident through the rear surface and minimize the light loss.

The bead layer 366 is formed by coating a plurality of beads on the back surface of the low refractive layer 365, and serves to improve luminance by scattering incident light.

A lower layer 370 is formed under the bead layer 366 to prevent interference with a substrate to be positioned under the optical sheet 360. In more detail, a light guide plate or a diffusion plate may be positioned below the optical sheet 360 according to the third exemplary embodiment of the present invention. The light guide plate or the diffusion plate may be formed by a plurality of beads of the bead layer 366. The surface may have a cracking phenomenon.

In this case, the rear layer 370 is formed under the bead layer 366 to prevent the splitting that may be caused by a plurality of beads, and the back layer 370 may be positioned below the optical sheet 360. It can serve to improve the adhesion with the substrate. In detail, the back layer 370 may be formed on the display screen and the wet-out phenomenon that may be caused by the optical sheet 360 and the light guide plate or the diffusion plate attached to each other according to the third embodiment of the present invention. Moiré pattern prevents appearance defects. That is, the back layer 370 covers the bead layer 366 and forms a smooth (flat) surface.

The back layer 370 may have the same refractive index as the low refractive layer 365.

7 is an exploded perspective view illustrating a liquid crystal display device including the optical sheet according to the first embodiment of the present invention. Here, although the optical sheet is shown assuming 2b, it is obvious that all of the above-described embodiments can be applied.

As shown in FIG. 7, the liquid crystal display device 100 includes a liquid crystal panel 110 and a backlight unit 120, and a support main 130 and a tower for modularizing the liquid crystal panel 110 and the backlight unit 120. The cover 140 and the cover bottom 150 is included.

The liquid crystal panel 110 plays a key role in image expression. The liquid crystal panel 110 includes first and second substrates 112 and 114 bonded to each other with a liquid crystal layer interposed therebetween.

Although not shown in the drawings, a plurality of gate lines and data lines intersect and define pixels on the inner surface of the first substrate 112, which is commonly referred to as a lower substrate or an array substrate, under the premise of an active matrix method. A thin film transistor (TFT) is provided to correspond one-to-one with the transparent pixel electrode formed in each pixel.

In addition, the inner surface of the second substrate 114 called the upper substrate or the color substrate includes, for example, color filters of red (R), green (G), and blue (B) colors corresponding to each pixel. A black matrix covering each other and covering non-display elements such as a gate line, a data line, and a thin film transistor is provided, and a transparent common electrode covering them is provided. Here, the transparent common electrode may be formed on the first substrate 112.

In addition, first and second polarizing plates (not shown) for selectively transmitting only specific light may be attached to outer surfaces of the first and second substrates 112 and 114, respectively.

A 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 the side of the support main 130 or the cover bottom 150 may be properly folded to be in close contact.

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 driver circuit transmitted through the printed circuit board 117, the signal of the data driving circuit is turned on. The voltage is transmitted to the corresponding pixel electrode through the data line, and 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.

The back of the liquid crystal panel 110 is provided with a backlight unit 120 for supplying light to display the 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, the reflector 125, and the light guide plate 123 mounted on the reflector 125. And an optical sheet 160 interposed thereon.

An LED 129a is used as the light source, and each of the plurality of LEDs 129a is spaced at regular intervals and mounted on an LED printed circuit board (PCB) 129b to form an LED assembly 129.

In this case, 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 the plurality of LEDs 129a.

The LED assembly 129 is fixed in position such as adhesive so that light emitted from the plurality of LEDs 129a faces the light incident part of the light guide plate 123.

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

Here, an LED housing (not shown) may be provided on the rear surface of the LED assembly 129 to more efficiently discharge 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 and is located between the LED assembly 129 and the cover bottom 150, the back of the LED printed circuit board 129b and one side of the plurality of LEDs (129a). It can be composed of a B-shaped vertically bent to surround.

The reflector plate 125 has a rectangular plate shape and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of the light.

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

The light guide plate 123 has a rectangular plate shape, and may include a pattern of a specific shape on the rear surface to supply a uniform surface light source.

In this case, the pattern may be configured in various ways such as an elliptical pattern, a polygonal pattern, a hologram pattern, and the like to guide the light incident into the light guide plate 123. The lower surface of the light guide plate 123 is formed by a printing method or an injection method.

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

The optical sheet 160 interposed above the light guide plate 123 diffuses and condenses the light converted into the surface light source by the light guide plate 123 so that a more uniform surface light source is incident on the liquid crystal panel 110.

Here, the optical sheet 160 may be an optical sheet having a conventional prism pattern formed by each of the first optical pattern 163 and the second optical pattern 169 acting as each optical sheet using the base layer 161 in common. It is characterized by having the same optical characteristics as at least two sheets used.

In addition, the optical sheet 160 according to the present invention is further included by including a low refractive index layer 165 formed to cover the first optical pattern 163 and having the lowest refractive index among the constituent layers constituting the optical sheet 160. By preventing the first optical pattern 163 formed of a plurality of inverse prism patterns from being exposed to the outside, interference with the light guide plate 123 disposed under the optical sheet 160 is prevented, and the amount of light reflection is reduced to reduce light loss. Minimize. That is, most of the light incident through the light guide plate 123 passes through the first optical pattern 163 and the second optical pattern 169 of the optical sheet 160 through the low refractive layer 165, thereby increasing luminance. There is an advantage.

In addition, the optical sheet 160 is provided with a concave-convex pattern (266 in FIG. 3) on the back surface of the low refractive layer 165, or the incident light scattering and diffusion by coating a plurality of beads (366 in FIG. 4) The optical efficiency can be further improved.

As such, by applying the optical sheet 160 according to the present invention, it is not necessary to use two optical sheets having a prism pattern as in the related art, and a separate diffusion sheet can be omitted. In addition, since the base layer is used in common, the thickness of the base layer is reduced and there is an advantage in that a lightweight, thin optical sheet can be realized. In addition, the component cost of the base layer is reduced, and further, the manufacturing cost of the entire liquid crystal display device can be reduced.

Although not shown in the drawings, an optical sheet may be further included between the light guide plate 123 and the optical sheet 160 or an upper portion of the optical sheet 160 to further increase optical characteristics.

The liquid crystal panel 110 and the backlight unit 120 described above are modularized through the support main 130, the top cover 140, and the cover bottom 150.

The support main 130 has a rectangular frame shape and separates the liquid crystal panel 110 and the backlight unit 120 and surrounds the edges of the liquid crystal panel 110 and the backlight unit 120.

The top cover 140 is formed to surround the front edge of the liquid crystal panel 110 and to open the front surface of the liquid crystal panel 110 so that an image implemented in the liquid crystal panel 110 can be displayed.

In addition, the cover bottom 150, on which the backlight unit 120 is seated and which is the basis of the entire structure of the liquid crystal display device 100, accommodates the backlight unit 120.

Accordingly, the liquid crystal panel 110 and the backlight unit 120 have a top cover 140 covering the top edge of the liquid crystal panel 110 and the backlight unit 120 while the edge is surrounded by the support main 130 having a rectangular frame shape. The cover bottom 150 covering the back surface is coupled in front and rear, respectively, and is integrated and modularized through the support main 130.

As it is modularized as described above, the light emitted from the LED assembly 129 of the backlight unit 120 is incident into the light guide plate 123 through the light incident part of the light guide plate 123, and then, toward the liquid crystal panel 110 therein. It is refracted and processed into a more uniform surface light source of high quality while being passed through the optical sheet 160 together with the light reflected by the reflector 125 to be supplied to the liquid crystal panel 110.

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

On the other hand, the above has been described with an example of 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, for example, but not limited to this, a plurality of LED assemblies are disposed below the liquid crystal panel. The present invention can also be applied to a liquid crystal display device in which a direct type backlight unit is applied. In this case, the light guide plate may be omitted, and the diffusion plate may be disposed to be spaced apart from the reflective plate at a predetermined interval, and the optical sheet according to the present invention may be disposed above the diffusion plate.

The embodiments of the present invention as described above are merely exemplary, and those skilled in the art may freely modify the present invention without departing from the gist of the present invention. Therefore, the protection scope of the present invention shall include the modifications of the present invention within the scope of the appended claims and equivalents thereof.

100: liquid crystal display 110: liquid crystal panel
120: backlight unit 160: optical sheet
161: base layer 163: first optical pattern
165, 265, 365: low refractive layer 169: second optical pattern
266: uneven pattern 366: bead layer
370: back layer

Claims (11)

A liquid crystal panel;
A backlight unit including an optical sheet positioned on a rear surface of the liquid crystal panel and a light source positioned on one side of the optical sheet;
The optical sheet is
A base layer, a first optical pattern formed under the base layer and having a first refractive index, a low refractive layer covering the first optical pattern and having a second refractive index, and formed on an upper portion of the base layer; A second optical pattern having a refractive index of 3;
The low refractive layer has a second thickness thicker than the first optical pattern,
And a concave-convex pattern including rounded concave portions and convex portions formed on a rear surface of the low refractive layer.
The method of claim 1,
The first optical pattern is a plurality of inverse prism pattern,
And the second optical pattern is one of a plurality of prism patterns including an acid and a plurality of semicircle patterns including a curved surface.
The method of claim 2,
And the second optical pattern has a wave shape along a longitudinal direction.
The method of claim 1,
The first refractive index is equal to or less than the third refractive index, or less than the third refractive index,
And the second refractive index is greater than that of air and less than the first and third refractive indices.
The method of claim 1,
And a first pitch of the first optical pattern and a second pitch of the second optical pattern are different from each other.
The method of claim 1,
And a first angle of an acid of the first optical pattern is smaller than a second angle of an acid of the second optical pattern.
delete delete delete The method of claim 1,
And the second optical pattern includes a urethane-based elastic additive.
A base layer;
A first optical pattern formed under the base layer and having a first refractive index;
A low refractive layer covering the first optical pattern and having a second refractive index; And
A second optical pattern formed on the base layer and having a third refractive index,
The low refractive layer has a second thickness thicker than the first optical pattern,
An optical sheet comprising a concave-convex pattern including a rounded concave portion and a convex portion formed on a rear surface of the low refractive layer.

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