KR102664505B1 - Display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device including a backlight unit capable of improving light efficiency and brightness.
A feature of the present invention is to position a composite optical sheet including a light condensing part in which inverted prism mountains with an apex angle of 66° (±2°) are arranged outside the lower polarizer of the liquid crystal panel, a reflective polarizing part, and a light diffusion adhesive. , the embossed pattern of the lenticular lens on the lower surface of the composite optical sheet, and the engraved pattern with a burr formed along the edge at the vertex of the lenticular lens of the embossed pattern are positioned, and the depth-to-width ratio of the engraved pattern is It is set to satisfy 12 to 15%, and the height of the burr of the intaglio pattern is set to 75 to 85% of the depth of the intaglio pattern.
Through this, it is possible to provide a lightweight and thin backlight unit, and it also simplifies the assembly process and improves productivity and competitiveness.
In addition, light loss can be minimized, visibility can be improved, and moiré and hot bands can also be prevented, and higher brightness can be realized without reducing the half depth angle compared to a typical liquid crystal display device. there is.

Description

Liquid crystal display device {Display device}

The present invention relates to a liquid crystal display device including a backlight unit capable of improving light efficiency and brightness.

Recently, with the development of information technology and mobile communication technology, display devices that can visually display information have been developed. Display devices are largely divided into self-luminous displays with luminous characteristics and other external factors to display images. It is classified as a non-emissive display that can

An example of a non-emissive display, which is a device that does not have its own light-emitting element, is LCD (Liquid Crystal Display).

Therefore, LCD, which is a non-emissive display, requires a separate light source. A backlight unit with a light source on the back is provided to irradiate light toward the front of the LCD, and only through this, an identifiable image is realized.

On the other hand, since the backlight unit stacks a light source and a number of optical sheets with different functions, the assembly process is cumbersome and requires detailed attention during work. Therefore, it causes problems of reduced productivity and competitiveness due to reduced workability and reduced product yield.

In addition, the number of sheets increases the overall thickness of the backlight unit, increases the manufacturing cost, and also reduces brightness due to light loss through the optical sheets. In addition, problems such as quality defects such as moire caused by mutual interference between optical sheets also occur.

The present invention is intended to solve the above problems, and its first purpose is to provide a lightweight and thin backlight unit by providing an integrated optical sheet that integrates parts of a plurality of films to reduce the thickness, and also simplifies the assembly process. The second purpose is to improve productivity and competitiveness.

In addition, the third purpose is to provide a backlight unit with improved quality by minimizing light loss and occurrence of moiré, etc.

In order to achieve the purpose as described above, the present invention is a liquid crystal panel, upper and lower polarizers located on both sides of the liquid crystal panel, and attached to the lower polarizer, and includes a light concentrator, a reflective polarizer, and a diffusion adhesive. A composite optical sheet including a composite optical sheet, located below the composite optical sheet, an embossed pattern protruding from the lower surface along a first direction across the light receiving surface from the light receiving surface, and a plurality of embossed patterns along the longitudinal direction from the apex of the embossed pattern. It includes a multi-pattern light guide plate including an engraved pattern positioned at regular intervals, an LED assembly arranged along the light receiving surface, and a reflector located below the multi-pattern light guide plate, and a burr (burr) along the edge of the engraved pattern. ) provides a liquid crystal display device in which a protruding liquid crystal display device is provided.

At this time, the intaglio pattern satisfies a depth-to-width ratio of 12 to 15%, and the height of the burr satisfies 75 to 85% of the depth of the intaglio pattern.

In addition, the intaglio pattern is located at a higher density per unit area as the distance from the light incident surface increases. In the embossed pattern, lenticular lenses are arranged in rows to protrude, and the intaglio pattern has a concave circular or oval shape, and has a cross section. is hemispherical in shape.

At this time, the light collection unit includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction, and the lens layer has an apex angle of (66-2)° to (66+2)°. It is made of a prism, and the light collecting part includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction, and the lens layer is a first prism located in one direction where the LED assembly is located. It includes a surface, a second prism surface forming a vertex angle with the first prism surface, and a third prism surface extending from the second prism surface to the opposite side of the first prism surface.

In addition, the light concentrator includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction, wherein the lens layer includes a first prism surface located in one direction in which the LED assembly is located, It includes a second prism surface that is convexly curved away from the first prism surface, and the light diffusion adhesive includes light diffusion beads.

As described in detail above, according to the present invention, inverted prisms having an apex angle of (66-2)° to (66+2)° are arranged on the outside of the lower polarizer of the liquid crystal panel, a light collecting part, a reflective polarizing part, and a light diffusion part. The composite optical sheet containing the adhesive is positioned, and the embossed pattern of the lenticular lens is placed on the lower surface below the composite optical sheet, and a plurality of burrs are formed along the edges at regular intervals at the apex of the lenticular lens of the embossed pattern. The engraved pattern is positioned so that the depth-to-width ratio of the engraved pattern satisfies 12 to 15%, and the height of the burr of the engraved pattern is set to 75 to 85% of the depth of the engraved pattern, making it lightweight and It has the effect of providing a thin backlight unit, and also has the effect of simplifying the assembly process and improving productivity and competitiveness.

In addition, it has the effect of minimizing light loss and improving visibility, while also preventing the occurrence of moiré and hot bands, and also does not reduce the angle at half depth compared to a typical liquid crystal display device. This has the effect of realizing higher brightness without reducing the intensity of the light.

1 is a cross-sectional view schematically showing a liquid crystal display device according to an embodiment of the present invention.
Figure 2 is a cross-sectional view schematically showing the composite optical sheet according to an embodiment of the present invention attached to the outer surface of the lower polarizer through a light diffusion adhesive.
3A to 3B are cross-sectional views schematically showing various structures of lens layers of a composite optical sheet.
Figure 4a is a rear perspective view of a multi-pattern light guide plate according to an embodiment of the present invention.
Figure 4b is a cross-sectional view schematically showing an intaglio pattern.

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

Figure 1 is a cross-sectional view schematically showing a liquid crystal display device according to an embodiment of the present invention, and Figure 2 is a schematic view showing the composite optical sheet according to an embodiment of the present invention attached to the outer surface of the lower polarizer through a light diffusion adhesive. It is a cross-sectional view shown as .

3A to 3B are cross-sectional views schematically showing various structures of the lens layers of the composite optical sheet.

As shown in FIG. 1, the liquid crystal display device 100 according to an embodiment of the present invention largely consists of a liquid crystal panel 110 and a backlight unit 120.

Let's look at each of these in more detail.

First, the liquid crystal panel 110 is a part that plays a key role in image expression of the liquid crystal display device 100, and is interposed between the first substrate 112 and the second substrate 114 that are bonded facing each other. It includes a liquid crystal layer (not shown).

Although not shown in the drawing, on the inner surface of the first substrate 112, called the lower substrate or array substrate, a plurality of gate lines and data lines intersect to define a pixel, and a thin film transistor is installed at each intersection. : TFT) is provided and connected in one-to-one correspondence with the transparent pixel electrode formed in each pixel.

And on the inner surface of the second substrate 114, called the upper substrate or color filter substrate, color filters of red (R), green (G), and blue (B) colors, for example, corresponding to each pixel, and these A black matrix is provided that surrounds each and covers the gate line, data line, and thin film transistor.

In addition, a transparent common electrode is provided that covers red (R), green (G), and blue (B) color filters and a black matrix.

In addition, upper and lower alignment films (not shown) that determine the initial molecular arrangement direction of the liquid crystal are interposed at the boundary between the first and second substrates 112 and 114 and the liquid crystal layer (not shown), and the first and second substrates To prevent leakage of the liquid crystal layer (not shown) filled between (112, 114), a seal pattern (not shown) is formed along the edges of both substrates (112, 114).

Additionally, upper and lower polarizing plates 115 and 116 that selectively transmit only specific light are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A printed circuit board (not shown) is connected along one edge of the liquid crystal panel 110 via a connecting member (not shown) such as a flexible circuit board or a tape carrier package (TCP).

Therefore, the liquid crystal panel 110 transmits the image signal of the data line to the corresponding pixel electrode when the thin film transistor selected for each gate line is turned on by the on/off signal of the thin film transistor scanned and transmitted to the gate line. is transmitted, and the resulting electric field between the pixel electrode and the common electrode changes the arrangement direction of the liquid crystal molecules, resulting in a difference in transmittance.

In addition, in the liquid crystal display device 100 according to an embodiment of the present invention, the display surface of the liquid crystal panel 110 faces forward so that the difference in transmittance shown by the liquid crystal panel 110 is expressed externally, and light is emitted from the back of the liquid crystal display device 100. A backlight unit 120 that supplies is provided.

A high-brightness surface light source implemented from the backlight unit 120 is provided to the liquid crystal panel 110, and the liquid crystal panel 110 displays an image.

The backlight unit 120 includes an LED assembly 129 arranged along one edge, a reflector 121, a multi-pattern light guide plate 220 mounted on the reflector 121, and an upper portion of the multi-pattern light guide plate 220. It includes a composite optical sheet 210 that is positioned.

The LED assembly 129 is a light source of the backlight unit 120 and includes a plurality of LEDs 129a and a PCB 129b on which the plurality of LEDs 129a are mounted at regular intervals.

At this time, the plurality of LEDs 129a emit light in the colors of red (R), green (G), and blue (B), respectively, toward the front toward the light receiving surface 221a of the multi-pattern light guide plate 220. By turning on all RGB LEDs 129a at once, white light can be created by mixing colors.

In particular, recently, to improve luminous efficiency and brightness, blue LED (129a) containing a blue LED chip with excellent luminous efficiency and brightness has been used, and 'cerium-doped yttrium aluminum garnet (YAG: Ce)' as a phosphor. That is, a blue LED 129a made of yellow phosphor is used.

The blue light emitted from the LED 129a passes through the phosphor and mixes with the yellow light emitted by the phosphor, thereby producing white light.

In addition to the LED assembly 129, a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used.

The multi-pattern light guide plate 220 on which the light emitted from the plurality of LEDs 129a is incident is the multi-pattern light guide plate 220 as the light incident from the LEDs 129a travels within the multi-pattern light guide plate 220 by total reflection several times. ) is evenly spread over a wide area to provide a surface light source to the liquid crystal panel 110.

Accordingly, the multi-pattern light guide plate 220 is made of a plastic material such as polymethylmethacrylate (PMMA), an acrylic transparent resin, which is one of the transparent materials capable of transmitting light, or polycarbonate (PC) series. It is manufactured in a flat type.

This multi-pattern light guide plate 220 has excellent transparency, weather resistance, and coloring properties, and thus induces diffusion of light when it passes through.

Additionally, the multi-pattern light guide plate 220 may include patterns 223 and 225 of specific shapes on the lower surface 221d to supply a uniform surface light source. Here, the patterns 223 and 225 are formed by mixing the embossed pattern 223 and the engraved pattern 225 in order to more efficiently guide the light incident into the multi-pattern light guide plate 220.

Here, the light incident surface 221a of the multi-pattern light guide plate 220 is defined in the longitudinal direction of the multi-pattern light guide plate 220, that is, the X-axis direction defined in the drawing, so the light incident surface 221a of the multi-pattern light guide plate 220 The LED assembly 129 located forward facing is also arranged in the X-axis direction defined in the drawing.

At this time, the embossed pattern 223 is in the longitudinal direction from the light incident surface 221a of the multi-pattern light guide plate 220 to the light incident surface 221b so as to have a straight line from the light incident surface 221a to the light incident surface 221b. By arranging adjacent to each other in a strip shape along the Y-axis direction defined as , multiple lenticular lenses in the form of repeated peaks and valleys are arranged in a row, each protruding. We will look at this in more detail later.

In addition, the reflector 121 located below the multi-pattern light guide plate 220 is made of white, and improves the brightness of the light by reflecting the light passing through the back of the multi-pattern light guide plate 220 toward the liquid crystal panel 110.

Here, the liquid crystal display device 100 according to an embodiment of the present invention has a composite optical sheet 210 located above the multi-pattern light guide plate 220, and the composite optical sheet 210 has a light concentrator 216 (see FIG. 2). and a reflective polarizing portion (215, see FIG. 2), and is attached to the outer surface of the lower polarizing plate 116 of the liquid crystal panel 110 through a light diffusion adhesive (211, see FIG. 2).

Although this composite optical sheet 210 includes only a light diffusion adhesive (211, see Figure 2), one light collecting part (216, see Figure 2), and one reflective polarizing part (215, see Figure 2), it is a multi-pattern light guide plate. Together with (220), a high-brightness and high-quality surface light source can be provided through the liquid crystal panel (110).

In particular, high brightness and visibility are improved through the light diffusion adhesive 211 (see FIG. 2), and it is also possible to prevent light efficiency from being reduced as multiple optical sheets are provided.

In addition, the liquid crystal display device 100 can be made lightweight and thin, and at the same time, the process of modularizing the liquid crystal display device 100 can be simplified to shorten assembly time and reduce material costs, thereby improving process efficiency. We will look at this in more detail later.

Although not shown, the liquid crystal panel 110 and the backlight unit 120 are integrated into a module through a case top, guide panel, and cover button.

Here, looking in more detail at the structure of the composite optical sheet 210 with reference to FIG. 2,

As shown in FIG. 2, the composite optical sheet 210 largely consists of a light collecting part 216 and a reflective polarizing part 215, where the light collecting part 216 includes a support layer 217 and a lower part of the support layer 217. It includes a lens layer 218 for condensing light in a plane.

Here, the support layer 217 of the light collecting part 216 is made of polycarbonate series, poly sulfone series, poly acrylate series, polystyrene series, etc. that can transmit light. It consists of polyvinyl chloride series, polyvinyl alcohol series, poly norbornene series, and polyester series.

And, the lens layer 218 formed below the support layer 217, more precisely, on the lower surface facing the multi-pattern light guide plate 220, is made of transparent acrylic resin, and is formed in the longitudinal direction of the composite light collection sheet 210. A plurality of inverted prism mountains 219a, 219b in the form of repeated peaks and valleys are arranged adjacent to each other in a strip shape, forming a row to protrude from the support layers 211a, 211b.

Here, the inverted prism mountains 219a and 219b of the lens layer 218, which are arranged protrudingly in rows along the longitudinal direction of the composite light collection sheet 210, are arranged to protrude in rows in the X-axis direction defined in the drawing, It is preferable that the longitudinal direction and the embossed pattern 223 of the lenticular lens formed on the lower surface 221d of the multi-pattern light guide plate 220 are perpendicular to each other.

Through this, the subject moiré (occurring between the inverted prism mountains 219a and 219b of the lens layer 218 of the composite light collection sheet 210 and the embossed pattern 223 formed on the lower surface 221d of the multi-pattern light guide plate 220) is reduced. While preventing moire) from occurring, luminance can also be improved.

That is, when the embossed pattern 223 of the lenticular lens formed on the lower surface 221d of the multi-pattern light guide plate 220 is arranged to protrude in a row in the Y-axis direction defined in the drawing, the lens layer of the composite light collection sheet 210 ( The inverted prism mountains 219a and 219b of 218) are arranged to protrude in a row in the The embossed pattern 223 of the lens and the longitudinal direction are perpendicular to each other.

Through this lens layer 218, the composite light collection sheet 210 focuses light onto the liquid crystal panel 110 located on the upper part of the composite light collection sheet 210, thereby providing a brightness increase effect.

Here, the inverted prism mountains 219a and 219b of the lens layer 218 may be composed of first and second prism surfaces 219a and 219b forming an apex angle α. The first and second prism surfaces 219a , 219b) are symmetrical to each other based on the direction perpendicular to the support layer 217, and the size of the apex angle (α) may be (66-2)° to (66+2)°.

At this time, the cross sections of the inverted prism mountains 219a and 219b become isosceles triangles. Within the above range, the front contrast ratio can be increased by concentrating more light in the front direction of the liquid crystal display device 100.

In addition to the inverted prism mountains 219a and 219b, the lens layer 218 may be made of an inverted prism with a polygonal cross-section as shown in FIGS. 3A to 3B. That is, as shown in FIG. 3A, the inverted prism is It may be formed to have a double angle by further including first and second prism surfaces 219a and 219b forming an apex angle α, and a third prism surface 219c.

Here, if the first prism surface 219a is formed to be located in one direction where the LED assembly 129, which is a light source, is located, the third prism surface 219c is formed from the second prism surface 219b to the first prism surface 219a. ) has a shape that extends to the opposite side.

In addition, as shown in FIG. 3B, the second prism surface 219b may be curved, that is, the second prism surface 219b may be curved to be convex away from the first prism surface 219a. It is formed. Accordingly, the light reflected from the second prism surface 219b is provided almost vertically toward the liquid crystal panel 110.

Additionally, instead of being formed as a curved surface, the second prism surface 219b may be composed of a combination of a plurality of planes in contact with the curved surface, and may have an overall polygonal shape.

At this time, the support layer 217 of the light collecting part 216 is characterized by having adhesive properties.

Accordingly, the light collection unit 216 and the reflective polarization unit 215 located above the light collection unit 216 are integrally bonded to each other through the adhesive properties of the support layer 217.

In this way, the reflective polarization part 215, which is combined with the light collection part 216, is a layer that transmits specific polarized light and reflects other specific polarized light, and its transmittance is 40 to 60 nm over the entire visible light wavelength range of 380 nm to 780 nm. It may be %. The reflective polarizer 215 serves to improve light efficiency by reflecting and recycling polarized light that would otherwise be absorbed without passing through the polarizers 115 and 116 of the liquid crystal display device 100.

The reflective polarizing portion 215 is made of a multi-layer type in which high refractive index layers and low refractive index layers are stretched and stacked alternately, or is made of a polymer dispersed type having a plurality of second polymers of different refractive indexes in a first polymer layer, or a second polymer layer. Instead of polymer, it may be of a polymer type with fibers, or may be of a wire grid type with a plurality of fine nanopatterns.

When shown and described as an example of the case where the reflective polarization unit 215 is made of a multi-layer type, the reflective polarization unit 215 includes a plurality of first and second refractive layers alternately stacked, and in this case, the first and second refractive layers are alternately stacked. The refractive layer may be a PEN layer, and the second refractive layer may be a COPEN layer.

The number of stacks of the first refractive layer and the second refractive layer in the reflective polarizer 215 may be tens to hundreds of layers, or more.

At this time, the first refractive layer and the second refractive layer may have different refractive indices in the direction of the reflection axis, and may have the same refractive index in the direction of the polarization axis (transmission axis) perpendicular to the reflection axis. Since the refractive index of the layer in the direction of the polarization axis is substantially the same, linearly polarized light vibrating in the direction of the polarization axis passes through the reflective polarization unit.

On the other hand, since the refractive indices of the first refractive layer and the second refractive layer in the direction of the reflection axis are different from each other, light vibrating in that direction may be reflected at the interface of the first refractive layer and the second refractive layer.

Here, the reflection efficiency at the interface between the first refractive layer and the second refractive layer is correlated with the corresponding wavelength and the thickness of the first and second refractive layers. As the wavelength is longer, the thickness of each layer showing the maximum reflection efficiency increases. . Therefore, in order to have excellent reflection efficiency in the entire visible light wavelength range, the reflective polarization unit 215 preferably includes a first refractive layer and a second refractive layer of various thicknesses.

For example, the reflective polarizer 215 includes a first refractive layer and a second refractive layer of a first thickness having maximum reflection efficiency in blue wavelengths, or a first thickness greater than the first thickness having maximum reflection efficiency in green wavelengths. It may include a first refractive layer and a second refractive layer of two thicknesses, and a first refractive layer and a second refractive layer of a third thickness greater than the second thickness having a maximum reflection efficiency at a red wavelength.

Through this reflective polarization unit 215, light efficiency is further improved.

In addition, a light diffusion adhesive 211 is located above the reflective polarization portion 215, and the composite optical sheet 210 is attached to the outer side of the lower polarizer 116 of the liquid crystal panel 110 through the light diffusion adhesive 211. It is attached, and through this, a lighter and thinner liquid crystal display device 100 can be implemented, and the modularization process can be further simplified, thereby further improving the efficiency of the process.

Here, the light diffusion adhesive 211 includes light diffusion beads 213, through which the composite optical sheet 210 according to an embodiment of the present invention can improve visibility even if it does not have a separate diffusion part. Higher brightness can also be achieved.

That is, the light diffusion adhesive 211 is located above the reflective polarizing portion 215, and attaches and fixes the composite optical sheet 210 to the outside of the lower polarizing plate 116.

This light diffusion adhesive 211 is made by including light diffusion beads 213 in a base polymer 211a, and the base polymer 211a contains a (meth)acrylic polymer (A). The (meth)acrylic polymer (A) contains, as monomer units, an alkyl (meth)acrylate (a1) constituting the main skeleton of the (meth)acrylic polymer (A), and an aromatic ring-containing (meth)acrylic monomer (a2). Contains

As the aromatic ring-containing (meth)acrylic monomer (a2), for example, benzyl (meth)acrylate can be used. Since the aromatic ring-containing (meth)acrylic monomer has positive intrinsic birefringence, it can be used in combination with alkyl (meth)acrylate and (meth)acrylate monomers having negative intrinsic birefringence.

At this time, when the aromatic ring-containing (meth)acrylic monomer is used in a predetermined amount together with the carboxyl group-containing monomer (a3) and the hydroxyl group-containing monomer (a4), an adhesive having the desired refractive index can be obtained.

This base polymer 221 has a refractive index of 1.47 or more, and more preferably has a refractive index of 1.49.

The light diffusion beads 213 contained in the base polymer 211a are made of polymer particles. The materials of the polymer particles include, for example, silicone resin, methacrylic resin, polystyrene resin, polyurethane resin, and melamine resin. You can.

Since these resins have excellent dispersibility in the base polymer 211a and an appropriate difference in refractive index with the base polymer 211a, a light diffusion adhesive 211 with excellent diffusion performance can be implemented.

That is, the light diffusion bead 213 preferably has a refractive index lower than that of the base polymer 211a. The refractive index of the light diffusion bead 213 is 1.30 to 1.70, and more preferably 1.45.

Here, the absolute value of the refractive index difference between the light diffusion bead 213 and the base polymer 211a is preferably greater than 0 and less than or equal to 0.2, and it is best to have a refractive index difference that exceeds 0 and is less than or equal to 0.05. desirable.

The light diffusion beads 213 have a particle diameter of 4 to 7 μm, and preferably have an average particle diameter of 6 μm and a content of 2.6 to 3.5% in the base polymer 211a, through which excellent light diffusion is achieved. A light diffusion adhesive (211) having high performance can be obtained.

That is, the composite optical sheet 210 according to an embodiment of the present invention is largely composed of only a light concentrator 216, a reflective polarizer 215, and a light diffusion adhesive 211. In this way, the light condenser 216 Even if it is composed only of the reflective polarizer 215 and the light diffusion adhesive 211, a high-brightness and high-quality surface light source is provided to the liquid crystal panel 110 together with the multi-pattern light guide plate 220 located at the bottom of the composite light diffusion sheet 210. It will be provided as.

At this time, the liquid crystal display device 100 according to an embodiment of the present invention improves visibility through the light diffusion adhesive 211, and also prevents light efficiency from being reduced as multiple optical sheets are provided. .

In addition, the liquid crystal display device 100 can be made lightweight and thin, and at the same time, the process of modularizing the liquid crystal display device 100 can be simplified to shorten assembly time and reduce material costs, thereby improving process efficiency.

Figure 4a is a rear perspective view of a multi-pattern light guide plate according to an embodiment of the present invention, and Figure 4b is a cross-sectional view schematically showing an engraved pattern.

As shown in FIG. 4A, the multi-pattern light guide plate 220 according to an embodiment of the present invention includes a light receiving surface 221a corresponding to the LED assembly (129 in FIG. 1), a light receiving surface 221b on the opposite side corresponding thereto, and An upper surface 221c connecting the light entering surface 221a and the receiving light surface 221b and emitting light, a lower surface 221d facing the reflector (121 in FIG. 1), and both sides 221e and 221f facing each other. It consists of

In addition, the lower surface 221d of the multi-pattern light guide plate 220 is provided with an embossed pattern 223 for condensing light. The embossed pattern 223 is the light receiving surface (221a) of the multi-pattern light guide plate 200. In order to have straightness toward 221b), peaks and valleys are repeated by arranging adjacent to each other in a strip shape along the Y-axis direction defined in the drawing, which is the longitudinal direction from the light incident surface 221a of the multi-pattern light guide plate 200 to the light incident surface 221b. A plurality of lenticular lenses are arranged in a row and each protrudes.

The embossed pattern 223 of this lenticular lens sets the light distribution angle of the multi-pattern light guide plate 220 in the direction perpendicular to the longitudinal direction (Y-axis direction) of the embossed pattern 223 and in the Z-axis direction defined in the drawing. , the luminance is improved.

At this time, it is desirable that the height of the embossed pattern 223 be lower than the width of the embossed pattern 134, and the ratio of the height of the embossed pattern 223 to the width of the embossed pattern 223 should be 20% or more. It is desirable to do so.

Through this, compared to a general light guide plate that emits light when the total reflection condition is broken, the light incident into the inside of the multi-pattern light guide plate 220 through the light-incoming surface 221a of the multi-pattern light guide plate 220 is transmitted to the light-incoming surface of the multi-pattern light guide plate 220. The amount of loss that escapes to the outside through 221b can be reduced, and the amount of light emitted through the upper surface 221c of the multi-pattern light guide plate 220 can be increased.

On the other hand, if the height of the embossed pattern 223 is higher than the width, the effect of increasing the amount of emitted light becomes insignificant, and the meaning of forming the embossed pattern 223 is lost.

Here, when the ratio of the height to width of the embossed pattern 223 is 10%, the difference in the amount of light near the light receiving surface 221a and the receiving light surface 221b is significant, and the amount of emitted light decreases, resulting in low straightness. You can. In addition, in the case where the height of the embossed pattern 223 is 20 to 50% of the width, the difference in the amount of light near the light receiving surface 221a and the light receiving surface 221b is small, and it can be seen that straightness is improved.

In other words, the higher the ratio of the height to width of the embossed pattern 223, the greater the straightness effect. When the ratio is 40% or more, it can be seen that the straightness effect is similar with little change.

Since this embossed pattern 223 protrudes toward the reflector (121 in FIG. 1), that is, in the opposite direction to the front of the multi-pattern light guide plate 220, it is possible to prevent the embossed pattern 223 from being recognized, and through this, It is possible to prevent moire phenomenon from occurring due to overlapping pixels of the shape of the embossed pattern 223 and the liquid crystal panel (110 in FIG. 1).

On the other hand, if the embossed pattern 223 is formed to protrude toward the liquid crystal panel (110 in FIG. 1), a moiré phenomenon may occur due to the overlap of the shape of the embossed pattern 223 and the pixels of the liquid crystal panel (110 in FIG. 1). , or the embossed pattern 223 may be recognized.

Such moiré phenomenon and pattern visibility are factors that deteriorate the image quality of the liquid crystal display (100 in FIG. 1).

At the vertex of the lenticular lens of the embossed pattern 223, a plurality of concave patterns 225, in which a portion of the embossed pattern 223 is concavely formed along the longitudinal direction of the embossed pattern 223, are overlapped at regular intervals. It is made up of a concave circular or oval shape, and its cross section is shaped like a hemisphere.

This engraved pattern 225 serves to further improve the light-gathering performance of the multi-pattern light guide plate 220.

Here, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention is characterized by forming a burr 227 along the edge of the engraved pattern 225 of the multi-pattern light guide plate 220. The burr 227 has a rough surface and serves to further diffuse light. Accordingly, the multi-pattern light guide plate 220 has light diffusion performance and visibility is also improved by the burr 227 provided in the engraved pattern 225.

On the other hand, as shown in Figure 4b, it is preferable that the intaglio pattern 225, which is formed by overlapping the embossed pattern 223, satisfies a ratio of depth (H) to width (D) of 12 to 15%, and the cathode pattern ( 225), when the ratio of depth (H) to width (D) is less than 12% or more than 15%, the luminance may be lowered compared to a typical liquid crystal display device, or the half depth angle may be implemented as narrow.

Below (Table 1) are the results of an experiment measuring the luminance and the half depth angle according to the ratio of the depth (H) to the width (D) of the intaglio pattern 225.

Sample A
(Width (D) 45um/Depth (H) 7um) Sample B
(Width (D) 45um/Depth (H) 6um) Sample C
(Width (D) 45um/Depth (H) 5um) Sample D
(Width (D) 45um/Depth (H) 4um) Sample E
(Width (D) 45um/Depth (H) 3um) Sample F
(Width (D) 45um/Depth (H) 2um) viewing angle
Half height angle V 31.5˚
Half height angle V 29˚
Half height angle V 26.5˚
Half height angle V 24.5˚
Half height angle V 23˚
Half height angle V 21.5˚ Light concentration (luminance) 99% 110% 121% 137% 154% 180%

In the above (Table 1), Sample A represents the viewing angle and light concentration (brightness) when the width (D) of the intaglio pattern 225 is 45um and the depth (H) is 7um, and Sample B represents the intaglio pattern (225). When the width (D) of 225) is 45um, the depth (H) represents the viewing angle and light concentration (brightness) when the depth (H) is 6um, and Sample C shows the depth (H) when the width (D) of the intaglio pattern 225 is 45um. H) represents the viewing angle and light concentration (brightness) when the width (D) of the intaglio pattern 225 is 45um and the depth (H) is the viewing angle and light concentration (brightness) when the intaglio pattern 225 is 4um. Sample E represents the viewing angle and light concentration (brightness) when the width (D) of the engraved pattern (225) is 45um and the depth (H) is 3um, and Sample F represents the engraved pattern (225). When the width (D) is 45um and the depth (H) is 2um, it represents the viewing angle and light concentration (brightness). At this time, in the multi-pattern light guide plate 220 according to an embodiment of the present invention, the engraved pattern 225 is formed to have a width (D) of 45 um, and when the depth (H) is formed to have a 7 um, a burr ( 227) is formed to have a height (h) of 5.6um, and when formed to have a depth (H) of 6um, the burr (227) is formed to have a height (h) of 4.8um.

In addition, when the depth (H) of the engraved pattern 225 is formed to have a height (h) of 5um, the burr (227) is formed to have a height (h) of 4.0um, and when the depth (H) is formed to have a depth (H) of 4um. The burr 227 is formed to have a height (h) of 3.2um, and when the depth (H) is formed to have a depth (H) of 3um, the burr (227) is formed to have a height (h) of 2.4um. , when the depth (H) is formed to have a height (h) of 1.6um, the burr (227) is formed to have a height (h) of 1.6um.

In the above (Table 1), the half-power angle is the azimuth at which light with an intensity equal to half of the maximum value of the light intensity is emitted. The narrower the half-power angle is, the more severe the difference in viewing angle characteristics occurs, which is not good. it means.

Looking at (Table 1), it can be seen that Sample A has a half-height angle similar to that of a typical liquid crystal display device (half-height angle V31˚), but the luminance is lowered. However, in contrast, Sample B has a similar half-height angle. It can be seen that the luminance has increased further.

In addition, it can be seen that Sample C, Sample D, Sample E, and Sample F all have increased luminance compared to a typical liquid crystal display device, but the half-height angle has all become smaller.

Here, Sample B, which has good characteristics in both half width angle and luminance, has a width (D) of 45 um and a depth (H) of 6 um of the engraved pattern 225, so the depth (H) compared to the width (D) The ratio is 13.3%, and Sample A has a depth (H) to width (D) ratio of 15.6%, and Sample C has a depth (H) to width (D) ratio of 11.1%, compared to the width (D) of the intaglio pattern (225). It can be confirmed that setting the depth (H) ratio to 12 to 15% is effective in increasing luminance and increasing the half depth angle.

In other words, it can be seen that it is desirable to ensure that the ratio of depth (H) to width (D) of the cathode pattern 225 satisfies 12 to 15%.

Meanwhile, in the explanation so far, it has been explained as an example that it is desirable for the intaglio pattern 225 to satisfy a depth (H) to width (D) ratio of 12 to 15%, but this satisfies the half depth angle of 28 to 32 degrees. As an optimal design element for this purpose, if the half depth angle is designed to be 28 degrees or less, the depth (H) to width (D) ratio of the intaglio pattern 225 can be designed to be 8 to 12%.

This is because, when the ratio of the depth (H) to the width (D) of the engraved pattern 225 is 8% or less, it is difficult to form the engraved pattern 225 with the burr 227 at the vertex of the embossed pattern 223, which is 12%. In the case of design above, the half height angle can be implemented narrowly. Here, the engraved pattern 225 is preferably formed so that the density per unit area increases as the distance from the LED assembly (129 in FIG. 1), which is the light source, increases. That is, the engraved pattern 225 is formed at the entrance of the multi-pattern light guide plate 220. It is formed so that the density per unit area increases as it moves from the light surface 221a to the light receiving surface 221b. Through this, the gap between the engraved patterns 225 adjacent to the light entering surface 221b of the multi-pattern light guide plate 220 is narrower than the gap between the engraved patterns 225 adjacent to the light entering surface 221a of the multi-pattern light guide plate 220. You lose.

In this way, by forming the density of the engraved pattern 225 to a higher density per unit area as it moves from the light incident surface 221a to the light incident surface 221b, the light traveling along the longitudinal direction of the embossed pattern 223 passes through the multi-pattern light guide plate 220. ) can be prevented from exiting to surfaces other than the upper surface 221c (for example, the light receiving surface 221b or the side surfaces 221e and 221f), thereby preventing light loss.

Here, the height (h) of the burr 227 is preferably formed to be 75 to 85% of the depth of the engraved pattern 225. This will be examined in more detail with reference to (Table 2) below. .

Below (Table 2) shows the burr 227 of the intaglio pattern 225 in the multi-pattern light guide plate 220 including the composite optical sheet 210 and the intaglio pattern 225 according to an embodiment of the present invention. This is the result of an experiment measuring the viewing angle and luminance according to the presence or absence of and height (h).

Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 viewing angle

Angle at half height V31˚
Angle at half height V23˚
Angle at half height V24˚
Angle at half height V29˚
Angle at half height V38˚ Light concentration (luminance) 100% 130% 125% 110% 92%

Prior to explanation, Sample 1 is a configuration of a typical liquid crystal display device, and consists of a composite optical sheet including a double light collection part, a diffusion part, and a light diffusion adhesive, and Sample 2 is a composite according to an embodiment of the present invention. In a multi-pattern light guide plate including an optical sheet and an engraved pattern, this shows a case where the engraved pattern is not provided with a burr. Additionally, Sample 3 represents the case where the height of the burr of the intaglio pattern is 20% of the depth of the cathode pattern, and Sample 4 represents the case where the height of the burr of the intaglio pattern is 80% of the depth of the cathode pattern. Sample 5 shows a case where the height of the burr of the intaglio pattern is 160% of the depth of the cathode pattern.

Looking at (Table 2), in the case of Sample 2 in which the burr 227 is not formed in the cathode pattern 225, the luminance is higher than that of Sample 1, which is a general liquid crystal display device, but the half-height angle is narrow. You can check that.

In addition, Sample 3, which is a case in which the burr 227 of the cathode pattern 225 is formed to have a height (h) of 20% compared to the depth (H) of the cathode pattern 25, also has a higher luminance compared to Sample 1. However, it can be seen that the half height angle appears narrow, and the burr 227 of the cathode pattern 225 is formed to have a height (h) of 160% compared to the depth (H) of the cathode pattern 225. In the case of Sample 5, the half depth angle appears similar to Sample 1, but it can be seen that the luminance is lowered.

On the other hand, when checking Sample 4, which is a case where the burr 227 of the cathode pattern 225 is formed to have a height (h) of 80% compared to the depth (H) of the cathode pattern 225, the luminance is Sample 4. You can see that it increases compared to 1, and the half height angle appears similar.

Here, the burr 227 serves to diffuse the light incident into the multi-pattern light guide plate 220 in the process of emitting it to the upper surface 221c of the multi-pattern light guide plate 220, so the burr If 227 is not provided or is formed to have a height (h) of 75% or less compared to the depth (H) of the intaglio pattern 225, the light diffusion performance is lowered, and the half-height angle is narrowed.

In addition, when the height (h) of the burr (227) is formed too high compared to the depth (H) of the engraved pattern (225), the light diffusion performance by the burr (227) becomes too large. , the luminance decreases.

Therefore, forming the height (h) of the burr 227 of the cathode pattern 225 to 75 to 85% of the depth (H) of the cathode pattern 225 provides a half height angle similar to that of a general liquid crystal display device. However, the luminance can be further increased.

That is, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention has an embossed pattern 223 of a lenticular lens on the lower surface 221d of the multi-pattern light guide plate 220, and a lenticular lens of the embossed pattern 223. The intaglio pattern 225, in which burrs 227 are formed along the edge, is located at the vertex of The height (h) of the burr 227 of the intaglio pattern 225 is formed to be 75 to 85% of the depth (H) of the intaglio pattern 225, and the lower surface of the multi-pattern light guide plate 220 The embossed pattern 223 of the lenticular lens and the engraved pattern 225, in which a burr 227 is formed along the edge of the lenticular lens of the embossed pattern 223, are positioned at (221d), and the multi-pattern An inverted prism mountain (219a, 219b in FIG. 2) with an apex angle (α in FIG. 2) ranging from (66-2)° to (66+2)° on the top of the light guide plate 220 is the embossed pattern of the multi-pattern light guide plate 220. A composite optical sheet (FIG. 2) including a light collecting part (216 in FIG. 2) arranged so that the longitudinal direction is perpendicular to (223), a reflective polarizing part (215 in FIG. 2), and a light diffusion adhesive (211 in FIG. 2). 210).

Through this, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention can further improve visibility and also prevent hot bands from occurring. Additionally, higher brightness can be achieved without reducing the half height angle compared to a typical liquid crystal display device.

In addition, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention places only the composite optical sheet (210 in FIG. 2) containing a light diffusion adhesive (211 in FIG. 2) on the multi-pattern light guide plate 220. By doing so, high brightness and visibility are improved through the light diffusion adhesive (211 in FIG. 2), and it is also possible to prevent light efficiency from being reduced as multiple optical sheets are provided.

In addition, the liquid crystal display device (100 in FIG. 1) can be made lightweight and thin, and at the same time, the process of modularizing the liquid crystal display device (100 in FIG. 1) is simplified, reducing assembly time and material costs, thereby increasing process efficiency. It can also be improved.

Below (Table 3) is an experimental result showing the optimal design results according to the configuration of the complex pattern light guide plate 220 of the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention compared with a typical conventional liquid crystal display device.

Sample 1 Sample 4 Sample 6 Sample 7 Sample 8 light concentration
(luminance) 100% 110% 107% 94% 143% viewing angle

Angle at half height V31˚
Angle at half height V29˚
Angle at half height V31˚
Angle at half height V29˚
Angle at half height V18˚ FOS Visibility OK, hot band OK Visibility OK
Hot Band OK Visibility NG
Hot Band OK Visibility OK
Hot Band OK Visibility NG
Hot Band NG

Prior to explanation, Sample 1 is a typical liquid crystal display device consisting of a composite optical sheet including a double light collection part, a diffusion part, and a light diffusion adhesive, and Sample 4 is a multi-pattern according to an embodiment of the present invention. A composition comprising a light guide plate, a light concentrator with an inverted prism mountain with an apex angle of (66-2)° to (66+2)°, and a composite optical sheet equipped with a light diffusion adhesive and a reflective polarizer on top of the multi-pattern light guide plate. represents. Sample 6 consists of a composite optical sheet equipped with a light collecting part, a light diffusion adhesive, and a reflective polarizing part, and an embossed pattern and an engraved pattern are formed on the upper surface of the light guide plate.

And Sample 7 is a composite optical sheet equipped with a light collecting part, a light diffusion adhesive, and a reflective polarizing part, and a positive and negative pattern is formed on the lower surface of the light guide plate, and the apex angle of the inverted prism mountain of the light collecting part is formed at 70 degrees. Sample 8 shows a configuration in which an embossed pattern and an engraved pattern are formed on the lower surface of the light guide plate, and the composite optical sheet located on the upper part of the light guide plate includes only one light concentrator and a reflective polarizer.

Here, visibility indicates that the embossed pattern 223 and the engraved pattern 225 are visible. When the embossed pattern 223 is visible, the moiré phenomenon occurs due to overlap with the pixels of the liquid crystal panel (110 in FIG. 1). This can be done, and when the engraved pattern 225 is visible, the area where the engraved pattern 225 is formed is displayed as a black dot, so poor visibility means that the image quality of the liquid crystal display device (100 in FIG. 1) is poor.

In addition, the hot band is a boundary between light and dark at the edge of the liquid crystal display (100 in FIG. 1), where the surface light source implemented from the backlight unit (120 in FIG. 1) spreads evenly across the front of the liquid crystal panel (110 in FIG. 1). It occurs because you are not hired. This poor hot band also means that the image quality of the liquid crystal display (100 in FIG. 1) is poor.

Looking at the above (Table 3), Sample 6 has a similar half height angle compared to Sample 1, a typical liquid crystal display device, and the luminance is further increased, but it can be seen that visibility due to the pattern is poor.

In addition, it can be confirmed that Sample 7 has a similar half-height angle to Sample 1 and that visibility due to the pattern is also good, but the luminance is low.

On the other hand, Sample 4 is good in both pattern visibility and hot band, luminance also increases further compared to Sample 1, and it can be seen that the half depth angle is also formed similarly.

And, looking at Sample 8, even though both the embossed pattern 223 and the engraved pattern 225 are provided on the lower surface 221d of the light guide plate, the composite optical sheet (210 in FIG. 2) located on the upper part of the light guide plate uses the light diffusion adhesive. If it is not included, the luminance increases compared to Sample 1, which is a general liquid crystal display device, but it can be seen that the visibility and hot band due to the pattern are both poor, and the half depth angle is also poor.

That is, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention has an embossed pattern 223 of a lenticular lens on the lower surface 221d of the multi-pattern light guide plate 220, and a lenticular lens of the embossed pattern 223. A concave pattern 225 with a burr 227 formed along the edge is positioned at the apex of An inverted prism mountain (219a, 219b in FIG. 2) of 66+2)° is arranged to be perpendicular to the embossed pattern 223 of the multi-pattern light guide plate 220 in the longitudinal direction (216 in FIG. 2), and a reflection By positioning the composite optical sheet (210 in FIG. 2) containing the polarizing part (215 in FIG. 2) and the light diffusion adhesive (211 in FIG. 2), visibility can be improved, but moiré and hot bands occur. In addition, it is possible to achieve higher brightness without reducing the half-height angle compared to a typical liquid crystal display device.

As described above, the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention has an apex angle (α in FIG. 2) outside the lower polarizer (116 in FIG. 2) of the liquid crystal panel (110 in FIG. 1). A light concentrator (216 in FIG. 2) in which inverted prism mountains (219a, 219b in FIG. 2) ranging from (66-2)° to (66+2)° are arranged, a reflective polarizer (215 in FIG. 2), and a light The composite optical sheet (210 in FIG. 2) containing the diffusion adhesive (211 in FIG. 2) is positioned, and the embossed pattern 223 of the lenticular lens is placed on the lower surface 221d below the composite optical sheet (210 in FIG. 2). And, the engraved pattern 225, in which a burr 227 is formed along the edge, is located at the vertex of the lenticular lens of the embossed pattern 223, and at this time, the depth (D) compared to the width (D) of the engraved pattern (225) is positioned. The H) ratio is set to satisfy 12 to 15%, and the height (h) of the burr (227) of the intaglio pattern (225) is formed to be 75 to 85% of the depth (H) of the intaglio pattern (225). , it is possible to provide a lightweight and thin backlight unit, and the assembly process is simplified and productivity and competitiveness are also improved.

In addition, light loss can be minimized, visibility can be improved, moiré and hot bands can also be prevented, and higher brightness can be achieved without reducing the half depth angle compared to a typical liquid crystal display device.

Meanwhile, in the description so far, it has been explained and shown that the embossed pattern 223 formed on the lower surface 221d of the multi-pattern light guide plate 220 is made of a lenticular lens, but the embossed pattern 223 has a cross-section in addition to a lenticular lens. It may be made of a prism, a polygonal prism, a micro lens pattern, an emboss pattern, or a combination thereof.

In addition, although it is explained and shown in the drawing that the height of each embossed pattern 223 is the same, each embossed pattern may have a different height.

In addition, in the drawing, each embossed pattern 223 is shown to be spaced apart at a certain interval, and the lower surface 221d of the multi-pattern light guide plate 220 is partially exposed between each embossed pattern 223. However, each embossed pattern 223 is connected to each other. It may be formed in close contact.

In addition, in the description so far, it has been shown and explained that the engraved pattern 225 is located at the vertex of the lenticular lens of the embossed pattern 223, but the ratio of the width (D) to depth (H) of the engraved pattern 225 is not clear. If it can be implemented properly, it may be located in addition to the vertex of the lenticular lens of the embossed pattern 223. The present invention is not limited to the above embodiments, and can be implemented with various changes without departing from the spirit of the present invention.

220: Multi-pattern light guide plate
221a: light receiving surface, 221b: receiving light surface, 221c: upper surface, 221d: lower surface, 221e, 221f: side
223: Embossed pattern
225: Engraved pattern
227: burr

Claims (11)

a liquid crystal panel;
upper and lower polarizers located on both sides of the liquid crystal panel, respectively;
a composite optical sheet attached to the lower polarizing plate and including a light collecting part, a reflective polarizing part, and a light diffusion adhesive;
It is located below the composite optical sheet, and has an embossed pattern on the lower surface that protrudes along a first direction across the light receiving surface from the light receiving surface, and a plurality of intaglios located at regular intervals along the longitudinal direction at the vertex of the embossed pattern. A multi-pattern light guide plate including a pattern;
an LED assembly arranged along the light receiving surface;
Reflector located below the multi-pattern light guide plate
Includes,
Burrs protrude along the edges of the engraved pattern,
The height of the burr satisfies 75 to 85% of the depth of the engraved pattern.
Liquid crystal display device.
According to claim 1,
The intaglio pattern is a liquid crystal display device that satisfies a depth-to-width ratio of 12 to 15%.
delete According to claim 1,
The liquid crystal display device in which the intaglio pattern is located at a higher density per unit area as the distance from the light incident surface increases.
According to claim 1,
In the embossed pattern, lenticular lenses are arranged in rows to protrude from each other,
The liquid crystal display device in which the engraved pattern is formed in a concave circular or oval shape and has a hemispherical cross section.
According to claim 1,
The light concentrator includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction,
The lens layer is a liquid crystal display device made of an inverted prism with an apex angle of (66-2)° to (66+2)°.
According to claim 1,
The light concentrator includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction,
The lens layer includes a first prism surface located in one direction where the LED assembly is located, a second prism surface forming a vertex angle with the first prism surface, and extending from the second prism surface to the opposite side of the first prism surface. A liquid crystal display device including a third prism surface.
According to claim 1,
The light concentrator includes a lens layer protruding and arranged in a row along a second direction perpendicular to the first direction,
The lens layer is a liquid crystal display device including a first prism surface located in one direction where the LED assembly is located, and a second prism surface that is convexly curved away from the first prism surface.
According to claim 1,
The light diffusion adhesive is a liquid crystal display device including light diffusion beads. According to claim 1,
A plurality of the embossed patterns extending parallel to each other are formed on the lower surface of the multi-pattern light guide plate,
The multiple embossed patterns have different heights.
Liquid crystal display device.
According to claim 1,
A plurality of the embossed patterns extending parallel to each other are formed on the lower surface of the multi-pattern light guide plate,
The embossed patterns adjacent to each other are spaced apart so that the lower surface is exposed.
Liquid crystal display device.