KR102436252B1 - Display device - Google Patents

Abstract

The present invention relates to a display device including a light-diffusing adhesive.
A feature of the present invention is to attach the composite optical sheet to the outside of the lower polarizing plate of the liquid crystal display through a light-diffusing adhesive. At this time, the light-diffusion adhesive is characterized in that it comprises a light-diffusion bead containing a plurality of air pockets therein.
In particular, by varying the volume of the air pocket contained in the light diffusion bead, the liquid crystal display realizes high brightness or improves visibility.
Alternatively, both high luminance and visibility are improved.
In addition, as a plurality of optical sheets are provided, it is possible to prevent a decrease in light efficiency, and it is possible to realize light weight and thinness of the liquid crystal display device, and at the same time, it is possible to simplify the process of modularizing the liquid crystal display device, thereby shortening the assembly time. And by reducing material cost, it is possible to also improve the efficiency of the process.

Description

Display device

The present invention relates to a display device including a light-diffusing adhesive.

Recently, as society enters the information age in earnest, interest in information displays that process and display a large amount of information is heightened, and as the demand to use portable information media increases, the display field has developed rapidly. In response to this, various light and thin display devices have been developed and are in the spotlight.

Specific examples of such a display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), an electroluminescence display device ( Electroluminescence Display device (ELD), organic light emitting diodes (OLED), etc. are mentioned. These display devices show excellent performance of thinness, light weight, and low power consumption, so that the existing cathode ray tube (CRT) can be used. are being replaced quickly.

On the other hand, in recent years, there is a constant demand for a display device capable of realizing a light weight and thin shape while improving high brightness and visibility, and research on a light diffusing adhesive, which is one of the measures to meet these demands, is being actively conducted.

The light-diffusing adhesive has a light-diffusion function by adding light-diffusing fine particles to the pressure-sensitive adhesive. Through this light-diffusing adhesive, a number of optical sheets are integrated to improve high brightness and visibility, while realizing a lightweight and thin display device. .

At this time, the light-diffusing adhesive exhibits a light-diffusion function due to the difference in refractive index between the adhesive and the light-diffusing fine particles. As the adhesive is mostly acrylic adhesive and the light-diffusing fine particle is silicone resin fine particles, the adhesive and the light The light diffusing function due to the refractive index difference of the diffusible fine particles is limited.

An object of the present invention is to provide a light-diffusion adhesive having an improved light-diffusion function to solve the above problems, and to provide a display device with improved high brightness and improved visibility.

Another object of the present invention is to provide a light-weight and thin display device.

In order to achieve the object as described above, the present invention includes a display panel, a polarizing plate positioned on one side of the display panel, and a light diffusion bead positioned on one side of the polarizing plate and having a surface curvature size of 30 to 100 nm. It provides a display device comprising a light-diffusing adhesive.

In this case, the light-diffusion bead includes a plurality of air pockets, the plurality of air pockets have a volume of 60ml/100g to 150ml/100g of the light-diffusion bead, and the light-diffusion bead has a refractive index of 1.45, and The light-diffusion beads are contained in the base polymer having a refractive index of 1.49, and the light-diffusion beads have a size of 4 to 7 μm, and have a content of 2.6 to 3.5% in the base polymer.

In addition, the display panel is a liquid crystal panel, and a composite optical sheet including first and second light collecting parts and a diffusion part is attached to the outside of the polarizing plate through the light diffusing adhesive, and the first and second light collecting parts are each a first First and second support layers, and first and second lens layers respectively provided above the first and second support layers, wherein the first and second lens layers are arranged adjacent to each other in a band shape along the longitudinal direction and second prism mounts are arranged to protrude in a row, and the first and second lens layers are perpendicular to each other in their respective longitudinal directions.

A fourth support layer is positioned between the second lens layer and the light-diffusing adhesive, and the diffusion unit includes a third support layer and first and second diffusion layers on both sides of the third support layer.

In addition, a light source is positioned under the composite optical sheet, the light sources are arranged along one edge of the light guide plate, or a plurality of light sources are arranged under the composite optical sheet, and the display panel includes first and second electrodes and a light emitting diode and the polarizing plate is attached to one side of the display panel through the light-diffusing adhesive.

As described above, according to the present invention, the composite optical sheet is attached to the outside of the lower polarizing plate of the liquid crystal display through a light-diffusing adhesive, in this case, the light-diffusing adhesive includes a light-diffusion bead containing a plurality of air pockets therein. By varying the volume of the air pocket contained inside the light diffusion bead, the liquid crystal display has the effect of realizing high brightness or improving visibility. Alternatively, there is an effect of improving both high luminance and visibility.

In addition, as a plurality of optical sheets are provided, there is an effect of preventing a decrease in light efficiency, and also, there is an effect of realizing light weight and thinness of the liquid crystal display device, and at the same time, the process of modularizing the liquid crystal display device is performed. By simplification, there is an effect of reducing assembly time and reducing material costs, thereby improving the efficiency of the process.

1 is a cross-sectional view schematically illustrating a liquid crystal display device according to a first embodiment of the present invention.
2 is a cross-sectional view schematically illustrating a state in which a composite optical sheet according to a first embodiment of the present invention is attached to the outer surface of a lower polarizing plate through a light-diffusing adhesive.
Figure 3a is experimental data of measuring the luminance ratio according to the content of the light-diffusion beads.
Figure 3b is experimental data of measuring the haze value according to the content of the light-diffusion beads.
4A and 4B are perspective cross-sectional views schematically showing a light diffusion bead equipped with an air pocket.
5A and 5B are schematic views schematically showing the surface curvature according to the volume of the air pocket of the light diffusion bead.
6A and 6B are schematic views schematically illustrating the scattering of light according to the surface curvature of the light diffusion bead.
Figure 7a is experimental data of measuring haze value according to the surface curvature size of the light diffusion bead.
7B is experimental data of measuring the luminance ratio according to the surface curvature size of the light-diffusion bead.
8 is a cross-sectional view schematically illustrating an organic light emitting display device according to a second exemplary embodiment of the present invention.

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

- 1st embodiment -

1 is a cross-sectional view schematically illustrating a liquid crystal display device according to a first embodiment of the present invention.

As shown, the liquid crystal display 100 according to the first embodiment of the present invention is largely composed of a liquid crystal panel 110 and a backlight unit 120 .

Let's take a closer look at each of these.

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

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

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

In addition, red (R), green (G), and blue (B) color filters and a transparent common electrode covering the black matrix are provided.

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

In addition, upper and lower polarizing plates 115 and 116 for selectively transmitting 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 through a connecting member (not shown) such as a flexible circuit board or a tape carrier package (TCP) along one edge of the liquid crystal panel 110 .

Accordingly, 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, the liquid crystal panel 110 transmits the image signal of the data line to the corresponding pixel electrode. is transmitted, and the arrangement direction of liquid crystal molecules is changed by the generated electric field between the pixel electrode and the common electrode, indicating a difference in transmittance.

And in the liquid crystal display device 100 according to the present invention, light is supplied from the rear surface of the liquid crystal panel 110 on the premise that the display surface of the liquid crystal panel 110 faces the front so that the difference in transmittance displayed by the liquid crystal panel 110 is expressed to the outside. A backlight unit 120 is provided.

The 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 reflection plate 121 , a light guide plate 123 seated on the reflection plate 121 , and a composite optical positioned above the light guide plate 123 . It includes a sheet 210 .

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 to be spaced apart from each other by a predetermined interval.

At this time, the plurality of LEDs 129a emit light having red (R), green (G), and blue (B) colors in a forward direction toward the light incident surface of the light guide plate 123 , and the plurality of RGB LEDs 129a ) can be turned on at once to realize white light by color mixing.

In particular, recently, in order to improve luminous efficiency and luminance, a blue LED 129a including a blue LED chip having excellent luminous efficiency and luminance is used, and as a phosphor, 'cerium-doped yttrium aluminum garnet (YAG:Ce)', That is, the blue LED 129a made of a 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 realizing 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 light guide plate 123 to which the light emitted from the plurality of LEDs 129a is incident is uniformly spread over a wide area of the light guide plate 123 while the light incident from the LEDs 129a travels within the light guide plate 123 by total reflection several times. Spread to provide a surface light source to the liquid crystal panel (110).

Accordingly, the light guide plate 123 is made of a plastic material such as polymethylmethacrylate (PMMA), which is an acrylic transparent resin, which is one of the transmissive materials that can transmit light, or a polycarbonate (PC) series. It is manufactured in a flat type.

The light guide plate 123 has excellent transparency, weather resistance, and colorability to induce light diffusion when light passes through.

In addition, the light guide plate 123 may include a pattern having a specific shape on its lower surface in order to supply a uniform surface light source. Here, the pattern may be variously configured such as an elliptical pattern, a polygonal pattern, a hologram pattern, etc. in order to guide the light incident into the light guide plate 123 . The pattern is formed on the lower surface of the light guide plate 123 by a printing method or an injection method.

In addition, the reflective plate 121 positioned below the light guide plate 123 reflects the light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the luminance of the light.

Here, in the liquid crystal display 100 according to the first embodiment of the present invention, the composite optical sheet 210 is positioned above the light guide plate 123 , and the composite optical sheet 210 includes the first and second light collecting parts 213a. , 213b (refer to FIG. 2 ) and a diffusion unit 213c (refer to FIG. 2 ), so that the light passing through the light guide plate 123 is diffused or condensed to provide a high-brightness surface light source to the liquid crystal panel 110 .

In particular, the composite optical sheet 210 is characterized in that it is attached to the outer surface of the lower polarizing plate 116 of the liquid crystal panel 110 through the light diffusion adhesive 220 .

Through this, the liquid crystal display 100 according to the first embodiment of the present invention has higher luminance and improved visibility.

In addition, as a plurality of optical sheets are provided, it is possible to prevent a decrease in light efficiency, and it is possible to realize light weight and thinness of the liquid crystal display device 100 , and at the same time, the process of modularizing the liquid crystal display device 100 can be performed. By simplification, the efficiency of the process can also be improved by reducing the assembly time and material cost. We will look at this in more detail later.

Although not shown, the liquid crystal panel 110 and the backlight unit 120 are integrally modularized through a case top, a guide panel, and a cover bottom.

On the other hand, the backlight unit 120 is divided into a side type and a direct type according to the position of the light source that emits light. Although the layered light type in which the light of the light source (=LED (129a)) emitted from the light source (=LED 129a) is refracted by a separate light guide plate 123 and emitted toward the liquid crystal panel 110 is taken as an example, a plurality of light sources ( = A direct light type in which light is incident by directly arranging the LED (129a)) is also applicable.

2 is a cross-sectional view schematically illustrating a state in which the composite optical sheet according to the first embodiment of the present invention is attached to the outer surface of the lower polarizing plate through a light-diffusing adhesive.

As shown, the composite optical sheet 210 is largely composed of a first light collecting part 213a, a second light collecting part 213b, and a diffusion part 213c, and the first light collecting part 213a has a first support layer ( 211a) and a first lens layer 215a for condensing light from the upper surface of the first support layer 211a, wherein the second light collecting part 213b positioned on the first light collecting part 213a includes: It consists of a second support layer 211b and a second lens layer 215b for condensing light from the upper surface of the second support layer 211b.

The diffusion portion 213c includes a third support layer 211c and first and second diffusion layers 219a and 219b positioned on both sides of the third support layer 211c.

Here, if we look at these layers in more detail, the first and second support layers 211a and 211b of the first and second light collecting parts 213a and 213b are polycarbonate-based, polysulfone that can transmit light. (poly sulfone) series, poly acrylate series, polystyrene series, polyvinyl chloride series, polyvinyl alcohol series, poly norbornene series , a polyester series, and the like.

In addition, the first and second lens layers 215a and 215b respectively formed on the first and second support layers 211a and 211b are made of a transparent acryl-based resin, and the length of the composite light collecting sheet 210 is A plurality of first and second prismatic mountains 217a and 217b in a form in which mountains and valleys are repeated by being adjacently arranged in a band shape along the direction are arranged to protrude from the first and second support layers 211a and 211b, respectively. .

Due to these first and second prism mounts 217a and 217b, the composite light collecting sheet 210 condenses the light to the liquid crystal panel (110 in FIG. 1) positioned on the composite light collecting sheet 210, thereby luminance. has a synergistic effect.

On the other hand, the first and second lens layers 215a and 215b, in addition to the first and second prism peaks 217a and 217b, may be formed of a prism having a polygonal cross-section, a micro lens pattern, a lenticular lens, an embossing pattern, or a combination thereof. may be

In addition, although the heights of the first and second prism peaks 217a and 217b are the same in the drawing, the heights of the first and second prism peaks 217a and 217b adjacent to each other may be different from each other. 2 The height of the prismatic acids 217a and 217b may be 10 μm to 40 μm, specifically, 10 μm to 30 μm.

In addition, the pitch of the first and second prism peaks 217a and 217b may also be different from each other, and the pitch corresponding to the bottom surface of the first and second prism peaks 217a and 217b is 10 μm to 60 μm, specifically 20 μm. It may be in the range of ㎛ to 60㎛.

In addition, the vertex angles of the first and second prism mountains 217a and 217b may be in the range of 80° to 100°, and within the above range, there may be a luminance improvement effect.

Here, in the drawing, the cross-sections of the first and second prism peaks 217a and 217b of the first and second lens layers 215a and 215b are the same, and the first and second lens layers 215a and 215b have the same cross-section. Although the longitudinal direction is shown to be in the same direction, the first and second lens layers 215a and 215b protrudingly arranged in a row along the longitudinal direction of the composite light collecting sheet 210 have their respective longitudinal directions perpendicular to each other. , the luminance is also improved while preventing pitch moire generated between optical patterns from occurring.

That is, when the first lens layer 215a is arranged to protrude in a column in the X-axis direction defined in the drawing, the second lens layer 215b forms a column in the Y-axis direction perpendicular to the X-axis direction defined in the drawing. The first and second lens layers 215a and 215b are arranged so that the longitudinal directions thereof are orthogonal to each other.

In addition, the diffusion portion 213c is positioned under the first and second light collecting portions 213a and 213b, that is, the diffusion portion 213c is disposed at the lowermost end of the composite optical sheet 210, and the light guide plate ( The light emitted from 123) of FIG. 1 is diffused to have a uniform distribution in a wide range.

In the diffusion portion 213c, the third support layer 211c and first and second diffusion layers 219a and 219b are positioned on both sides of the third support layer 211c, and the third support layer 211c serves to transmit light. Polycarbonate series, polysulfone series, polyacrylate series, polystyrene series, polyvinyl chloride series, polyvinyl alcohol series alcohol) series, poly norbornene series, polyester series, and the like.

Here, the first and second diffusion layers 219a and 219b include a light diffusion component such as a bead 215c, or the first and second diffusion layers 219a and 219b without the bead 219c. It can also be configured by forming a fine pattern on the lower surface of the

Through this, the first and second diffusion layers 219a and 219b diffuse the light by refracting and scattering the incident light and emitting the non-uniform light passing through the light guide plate (123 in FIG. 1) as uniform light. .

At this time, the bead 219c is included in the binder resin, and the bead 219c disperses the light incident on the first and second diffusion layers 219a and 219b, thereby preventing the light from being partially concentrated. There is this. As shown in FIG. 2 , the beads 219c in the first diffusion layer 219a have a uniform size, while the beads 219c in the second diffusion layer 219b have different sizes.

Here, the binder resin has high transparency, excellent light transmittance, and easy viscosity control. For example, an acrylic resin, a urethane resin, an epoxy resin, a vinyl resin, a polyester resin, or a polyamide resin may be used.

At this time, it is preferable that the second diffusion layer 219b has a haze characteristic of 90% to 95% of the light emitted from the third support layer 211c, and for this purpose, the bead 219c has a size of 2um to 15um. can have

In addition, in the first diffusion layer 219a, the bead 219c may have a size of 2 μm to 5 μm in order to diffuse the light incident to the third support layer 211c.

In addition, the first and second diffusion layers 219a and 219b that do not include the bead 219c have a feature that can adjust the light scattering angle according to the shape of the fine pattern (not shown). It can be configured in various ways, such as an elliptical pattern, a polygonal pattern, etc., and the collected light by using a hologram pattern to refract the light incident by the interference pattern in an asymmetrical direction. This can be made to spread at a more inclined angle.

In this case, the first prism acid 217a of the first lens layer 215a of the first light collecting part 213a and the second diffusion layer 219b of the diffusion part 213c have adhesive properties.

Accordingly, the first light collecting part 213a and the second light collecting part 213b form an integrally bonded state to each other through the adhesive properties of the first lens layer 215a of the first light collecting part 213a. The light collecting portion 213a and the diffusion portion 213c are integrally bonded to each other through the adhesive properties of the second diffusion layer 219b of the diffusion portion 213c.

That is, the first and second light collecting parts 213a and 213b and the diffusion part 213c are all integrally bonded together.

Here, the third support layer 211c of the diffusion part 213c serves as a base for supporting the entire composite optical sheet 210, and the first and second support layers 211a and 211b are the first and second light collecting parts ( Since only the first and second lens layers 215a and 215b of 213a and 213b are supported, respectively, the thickness of the first and second support layers 211a and 211b is made thinner than the thickness of the third support layer 211c. By forming, the overall thickness of the composite optical sheet 210 can be reduced.

As described above, the liquid crystal display device (100 in FIG. 1) according to the first embodiment of the present invention includes the composite optical sheet 210 on the upper portion of the light guide plate (123 in FIG. 1), so that the light efficiency is increased by the plurality of optical sheets. It is possible to prevent deterioration, so that it is possible to provide a liquid crystal display device ( 100 in FIG. 1 ) with improved light efficiency, and it is possible to reduce the thickness of the backlight unit ( 120 in FIG. 1 ) compared to the existing one having a plurality of optical sheets. .

Through this, it is possible to provide a light-weight and thin liquid crystal display device (100 in FIG. 1), and as the number of components is reduced, the modularization process of the liquid crystal display device (100 in FIG. 1) is simplified, reducing assembly time and materials Costs can be reduced, and process efficiency can be improved.

And, in the liquid crystal display device (100 in FIG. 1) according to the first embodiment of the present invention, the composite optical sheet 210 is applied to the lower polarizing plate 116 of the liquid crystal panel (110 in FIG. 1) through the light-diffusing adhesive 220. By attaching it to the outside of the , a lighter and thinner liquid crystal display device ( 100 in FIG. 1 ) can be realized, and the modularization process can be further simplified, thereby further improving the efficiency of the process.

In particular, as the light-diffusion adhesive 220 for attaching the composite optical sheet 210 to the outside of the lower polarizing plate 116 includes the light-diffusion bead 223, the liquid crystal display device according to the first embodiment of the present invention. (100 in FIG. 1) can implement higher luminance, and also improve visibility.

Looking at this in more detail, the light-diffusing adhesive 220 is positioned above the second light collecting part 213b and the second lens layer 215b to attach and fix the composite optical sheet 210 to the outside of the lower polarizing plate 116 . will make it

At this time, in order to further improve the fixing force of the composite optical sheet 210, a fourth support layer 211d may be further positioned above the second lens layer 215b, and the fourth support layer 211d is the composite optical sheet. 210 and the light-diffusing adhesive 220 serve to increase the adhesion area to each other to improve the fixing force, and also to protect the apex angle of the second prism mount 217b of the second lens layer 215b. will do

The fourth support layer 211d is a polycarbonate-based, polysulfone-based, polyacrylate-based, polystyrene-based, polyvinylchloride-based material that can transmit light. vinyl chloride) series, polyvinyl alcohol series, poly norbornene series, polyester series, and the like.

The light-diffusion adhesive 220 positioned above the fourth support layer 211d includes a light-diffusion bead 223 in the base polymer 221, and the base polymer 221 is a (meth)acrylic polymer (A). contains The (meth)acrylic polymer (A) is, as a monomer unit, 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 may 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 a predetermined amount of the aromatic ring-containing (meth)acrylic monomer is used together with the carboxyl group-containing monomer (a3) and the hydroxyl group-containing monomer (a4), an adhesive having a desired refractive index can be obtained.

The 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 223 contained in the base polymer 221 are made of polymer microparticles, and the material of the polymer microparticles includes, for example, silicone resin, methacrylic resin, polystyrene resin, polyurethane resin, and melamine resin. can

Since these resins have excellent dispersibility with respect to the base polymer 221 and an appropriate refractive index difference with the base polymer 221 , the light-diffusing adhesive 220 having excellent diffusion performance may be implemented.

That is, the light diffusing bead 223 is preferably lower than the refractive index of the base polymer 221 , and the refractive index of the light diffusing bead 223 is 1.30 to 1.70, more preferably 1.45.

Here, the absolute value of the refractive index difference between the light diffusion bead 223 and the base polymer 221 preferably exceeds 0 and preferably has a refractive index difference of 0.2 or less. desirable.

The light diffusion beads 223 have a particle diameter of 4 to 7 μm, have an average particle diameter of 6 μm on average, and preferably have a content of 2.6 to 3.5% in the base polymer 221, through which, excellent light diffusion It is possible to obtain a light-diffusing adhesive 220 having a performance.

Below (Table 1) is experimental data measuring the light diffusion performance of the light diffusion adhesive 220 according to the content of the light diffusion bead 223, and FIG. 3a is a luminance ratio according to the content of the light diffusion bead 223 is experimental data measured, and FIG. 3B is experimental data obtained by measuring haze values according to the content of the light-diffusion beads 223 .

division Ref. Surface curvature size (average 100nm) Surface curvature size (average 30nm) content ratio 3.17% 3.3% 3.5% 2.6% 4.7% Transmittance (%) 93 85 88 86 86 86 Haze (%) 76 23 28 37 35 57 Luminance ratio (%) 100 104 99 97 91 81 Exterior Lv.1 Lv.2 Lv.2 Lv.1 Lv.0 Lv.0

Prior to the description, the content ratio means the content of the light-diffusion beads 223 compared to the content of the base polymer 221 , the transmittance means the transmittance of the light-diffusion adhesive 220 , and the haze is the haze of the light-diffusion adhesive 220 . means value.

And, the luminance ratio is a result of measuring the luminance of the amount of light transmitted through the composite light-diffusion sheet 210 to which the light-diffusion adhesive 220 is applied, and the lower the Lv.

Referring to the above (Table 1) and the accompanying FIGS. 3A and 3B , it can be seen that the transmittance and haze value of the light-diffusion adhesive 220 are changed according to the content of the light-diffusion beads 223 , and also the surface curvature. As the size decreases, it can be seen that the haze value increases and the luminance decreases.

Therefore, by varying the content of the light-diffusion bead 223 of the light-diffusion adhesive 220 or the surface curvature size of the light-diffusion bead 223, the light-diffusion performance of the light-diffusion adhesive 220 can be adjusted. can confirm.

Here, the surface bending size of the light diffusion bead 223 can be adjusted by including a plurality of air pockets 225 inside the light diffusion bead 223 as shown in FIGS. 4A and 4B .

That is, the light diffusion beads 223 contained in the base polymer 221 of the light diffusion adhesive 220 according to the first embodiment of the present invention include a plurality of air pockets 225 therein. do it with

In particular, the surface curvature of the light diffusion bead 223 varies depending on the content of the plurality of air pockets 225 contained therein. .

The specific gravity of the light diffusion bead 223, the volume of the air pocket 225, and the surface curvature size of the light diffusion bead 223 may be arranged as shown in Table 2 below.

division Specific gravity of light diffusion beads The volume of the air pocket contained in the light diffusion bead Average surface curvature size of light diffusion bead
[Min ~ Max] #One 1.5 40ml/100g 10nm
[5 to 20] #2 One 60ml/100g 30nm
[20 to 50] #3 0.4 150ml/100g 100nm
[30 ~ 160] #4 0.085 700ml/100g 300nm
[60 ~ 400]

Prior to the description, the above (Table 2) shows the surface of the light diffusion bead 223 according to the specific gravity of the light diffusion bead 223 made of a silicone resin and the volume of the air pocket 225 contained in the light diffusion bead 223 It is experimental data measuring the bending size.

At this time, the refractive index of the light diffusion bead 223 is 1.45, and the surface bending size of the light diffusion bead 223 is derived by measuring the full width at half maximum interval through a scanning electron microscope (Scanning Electron Microscope). did.

And, the volume of the air pocket 225 was measured through the oil (oil) absorption.

Looking at the above (Table 2), the specific gravity of the light diffusion bead 223 and the volume of the air pocket 225 have a relationship in inverse proportion to each other, and the larger the volume of the light diffusion bead 223, the greater the light diffusion bead. It can be seen that the surface curvature size of 223 is also increased.

That is, as the volume of the air pocket 225 contained in the light diffusion bead 223 increases, the surface curvature of the light diffusion bead 223 also increases as shown in FIG. 5A , and the As the volume of the air pocket 225 contained therein is smaller, the surface curvature of the light diffusion bead 223 becomes smaller as shown in FIG. 5B .

At this time, when the surface curvature of the light-diffusion bead 223 is large as shown in FIG. 6a , the scattering of light by the light-diffusion bead 223 becomes small, and as shown in FIG. 6b , the light-diffusion bead 223 is The smaller the surface curvature of , the greater the scattering of light by the light diffusion bead 223 is.

Therefore, as the light-diffusion adhesive 220 varies the volume of the plurality of air pockets 225 contained in the light-diffusion bead 223, the surface curvature size of the light-diffusion bead 223 is varied through the light-diffusing adhesive (220) is to adjust the light diffusion performance.

Below (Table 3) is experimental data measuring the light diffusion performance of the light diffusion adhesive 220 according to the surface bending size of the light diffusion bead 223, and FIG. 7a is the surface bending size of the light diffusion bead 223. It is experimental data obtained by measuring the haze value according to , and FIG. 7B is experimental data obtained by measuring the luminance ratio according to the surface curvature size of the light diffusion bead 223 .

Surface curvature size (nm) Haze (%) Transmittance (%) Luminance ratio (%) Appearance elegance 10 65.34 88.12 84.15 very good 30 41.29 87.42 88.14 Great 100 24.07 86.3 102.63 usually 300 12.47 86.41 110.38 very bad

Prior to the description, the light diffusion bead 223 is made of a silicone resin, has a size of 6 to 7 μm, and has a refractive index of 1.45.

In addition, the base polymer 221 is made of an acrylic polymer, has a refractive index of 1.49, and the content of the light diffusion beads 223 is 3.2% compared to the content of the base polymer 221 .

In this case, the transmittance means the transmittance of the light-diffusion adhesive 220 , and the haze means the haze value of the light-diffusion adhesive 220 . And, the luminance ratio is a result of measuring the luminance of the amount of light transmitted through the composite optical sheet 210 to which the light-diffusing adhesive 220 is applied.

And, haze value and transmittance of the light-diffusing adhesive 220 were measured using a hazemeter.

Referring to the above (Table 3) and the accompanying FIGS. 7A and 7B, it can be seen that as the surface curvature size of the light diffusion bead 223 increases, the haze value decreases and the transmittance increases.

Here, when the surface curvature size of the light diffusion bead 223 is 10 nm, it has characteristics similar to the condition without surface curvature. become big

That is, when the surface curvature size of the light diffusion bead 223 is 10 nm, it has a high haze characteristic. Accordingly, the luminance of the composite optical sheet 210 is reduced, but visibility is improved, so that the appearance quality is very excellent.

In addition, when the surface curvature size is 300 nm, the effect of the difference in refractive index between the light diffusion bead 223 and the base polymer 221 is the smallest, and it can be seen that the scattering effect is very low.

However, when the surface curvature size is 300 nm, as it has a low haze value, the luminance of the composite optical sheet 210 is excellent, but visibility is very low, and it can be seen that the appearance quality is very poor.

This is similar to the configuration in which only the base polymer 221 without the light diffusion beads 223 is present.

Therefore, it is most preferable that the surface curvature of the light diffusion bead 223 has a size of 30 to 100 nm, and in order to improve luminance, it is preferable to have the surface curvature have a size of 100 nm, and in order to improve visibility, the surface curvature of 30 nm It is preferable to have a surface curvature size.

That is, the liquid crystal display device ( 100 in FIG. 1 ) according to the first embodiment of the present invention includes the light diffusion beads 223 containing the air pockets 225 inside the light diffusion adhesive 220 , so that the light diffusion beads By changing the surface curvature of 223, high brightness and visibility can be improved, and higher brightness can be realized or visibility can be further improved.

As described above, in the liquid crystal display device (100 in FIG. 1) according to the first embodiment of the present invention, the composite optical sheet 210 is positioned above the light guide plate (123 in FIG. 1), and the composite optical sheet 210 is Since it includes the first and second light condensing units 213a and 213b and the diffusion unit 213c, the light passing through the light guide plate (123 in FIG. 1) is diffused or condensed to form a liquid crystal panel (110 in FIG. 1) with high luminance. provides a light source.

In particular, the composite optical sheet 210 is attached to the outer surface of the lower polarizing plate 116 of the liquid crystal panel (110 in FIG. 1) through the light-diffusing adhesive 220, and at this time, the light-diffusion adhesive 220 is a plurality of It is characterized in that it comprises a light diffusion bead (223) containing the air pocket (225).

In particular, as the volume of the air pocket 225 contained in the light diffusion bead 223 is changed, the liquid crystal display ( 100 in FIG. 1 ) according to the first embodiment of the present invention realizes high brightness or improves visibility. will improve Alternatively, both high luminance and visibility are improved.

In addition, as a plurality of optical sheets are provided, it is possible to prevent a decrease in light efficiency, and in addition, it is possible to realize a light weight and thinness of the liquid crystal display device (100 in FIG. 1), and at the same time, a liquid crystal display device (100 in FIG. 1) ), the process efficiency can be improved by simplifying the process of modularizing the assembly time and reducing material costs.

- Second embodiment -

8 is a cross-sectional view schematically illustrating an organic light emitting display device according to a second exemplary embodiment of the present invention.

As shown, the organic light emitting diode display 300 according to the second embodiment of the present invention includes a first substrate 301 on which a driving thin film transistor DTr and a light emitting diode E are formed, the first substrate 301 and the It is composed of a second substrate 302 facing each other, and the first and second substrates 301 and 302 are spaced apart from each other through an adhesive protective layer 303 and bonded to each other to form a display panel.

Although not shown, if we look at this in more detail, a driving thin film transistor DTr is formed for each pixel region P on the upper portion of the first substrate 301, and a first electrode (DTr) connected to each driving thin film transistor DTr 311 ) and an organic light emitting layer 313 emitting light of a specific color on top of the first electrode 311 , and a second electrode 315 on the organic light emitting layer 313 .

The organic light emitting layer 313 expresses red, green, and blue colors. In a general method, a separate organic material emitting red, green, and blue light is patterned and used for each pixel area P.

The first and second electrodes 311 and 315 and the organic light emitting layer 313 formed therebetween constitute the light emitting diode E. In this case, the organic light emitting diode display 300 having such a structure includes the first electrode 311 as an anode and the second electrode 315 as a cathode.

In the organic light emitting display device 300 , when a predetermined voltage is applied to the first electrode 311 and the second electrode 315 according to a selected signal, holes injected from the first electrode 311 and the second electrode 315 are applied. ) are transported to the organic light emitting layer 313 to form excitons, and when these excitons are transitioned from an excited state to a ground state, light is generated and emitted in the form of visible light.

At this time, since the emitted light passes through the transparent second electrode 315 and goes out, the organic light emitting diode display 300 realizes an image.

In addition, in the organic light emitting display device 300 according to the second embodiment of the present invention, the polarizing plate 310 is positioned above the first substrate 301 of the display panel to prevent a decrease in contrast caused by external light. characterized.

That is, the organic light emitting display device 300 forms a polarizing plate 310 that blocks external light incident from the outside in the transmission direction of the light emitted through the organic light emitting layer 313 in the driving mode for realizing an image. will improve

The polarizing plate 310 is a circular polarizing plate for blocking external light, and includes a retardation plate and a linear polarizing plate attached to the outer surface of the first substrate 301 .

In this case, the stacking order of the linear polarizing plate and the retardation plate is preferably a structure in which the linear polarizing plate is disposed close to the incident direction of the external light and the retardation plate is disposed inside the linear polarizing plate.

Here, the organic light emitting display device 300 according to the second embodiment of the present invention is characterized in that the polarizing plate 310 is attached to the outer surface of the first substrate 301 through the light diffusion adhesive 220 .

The light-diffusion adhesive 220 includes the light-diffusion beads 223 in the base polymer 221 , and the base polymer 221 contains the (meth)acrylic polymer (A). The (meth)acrylic polymer (A) is, as a monomer unit, 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 may 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 a predetermined amount of the aromatic ring-containing (meth)acrylic monomer is used together with the carboxyl group-containing monomer (a3) and the hydroxyl group-containing monomer (a4), an adhesive having a desired refractive index can be obtained.

The 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 223 contained in the base polymer 221 are made of polymer microparticles, and the material of the polymer microparticles includes, for example, silicone resin, methacrylic resin, polystyrene resin, polyurethane resin, and melamine resin. can

Since these resins have excellent dispersibility with respect to the base polymer 221 and an appropriate refractive index difference with the base polymer 221 , the light-diffusing adhesive 220 having excellent diffusion performance may be implemented.

That is, the light diffusing bead 223 is preferably lower than the refractive index of the base polymer 221 , and the refractive index of the light diffusing bead 223 is 1.30 to 1.70, more preferably 1.45.

Here, the absolute value of the refractive index difference between the light diffusion bead 223 and the base polymer 221 preferably exceeds 0 and preferably has 0.2 or less. desirable.

The light diffusion beads 223 have a particle diameter of 4 to 7 μm, have an average particle diameter of 6 μm on average, and preferably have a content of 2.6 to 3.5% in the base polymer 221, through which, excellent light diffusion It is possible to obtain a light-diffusing adhesive 220 having a performance.

And, the light diffusion bead 223 contains a plurality of air pockets (225 in FIG. 6B).

Due to the plurality of air pockets (225 in FIG. 6B ) contained in the light diffusion bead 223 , the light diffusion bead 223 has a surface bending size of 30 to 100 nm.

Accordingly, the organic light emitting display device 300 according to the second embodiment of the present invention is implemented from the display panel through the light diffusing adhesive 220 in the process of preventing a decrease in contrast caused by external light through the polarizing plate 310 . The resulting light is processed more uniformly, realizing high luminance and improving visibility.

In addition, it is possible to prevent problems such as glare due to reflection of external light from occurring.

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

116: lower polarizing plate
210: composite optical sheets 211a, 211b, 211c, 211d: first to fourth support layers, 213a, 213b: first and second light collecting parts, 213c: diffusion, 215a, 215b: first and second lens layers; 217a, 217b: first and second prismatic acids, 219a, 219b: first and second diffusion layers, 219c: beads)
220: light diffusion adhesive (221: base polymer, 223: light diffusion bead)

Claims (12)

a display panel;
a polarizing plate positioned at one side of the display panel;
It is located on one side of the polarizing plate and contains a light-diffusing adhesive comprising a light-diffusing bead having a surface curvature size of 30 to 100 nm,
The light diffusion bead includes a plurality of air pockets, and the surface bending size of the light diffusion bead is determined by the content of the plurality of air pockets,
The display device, characterized in that as the surface curvature size of the light diffusion bead increases, the haze value decreases and the transmittance increases.
The method of claim 1,
The plurality of air pockets is a display device having a volume of 60ml/100g ~ 150ml/100g of the light diffusion bead.
The method of claim 1,
The light diffusing bead has a refractive index of 1.45, and the light diffusing bead is contained in a base polymer having a refractive index of 1.49.
4. The method of claim 3,
The light diffusion bead has a size of 4 ~ 7um,
A display device having a content of 2.6 to 3.5% in the base polymer.
The method of claim 1,
The display panel is a liquid crystal panel,
A display device for attaching a composite optical sheet including first and second light collecting parts and a diffusing part to the outside of the polarizing plate through the light diffusing adhesive.
6. The method of claim 5,
The first and second light collecting units are provided with first and second support layers, respectively, and first and second lens layers on the first and second support layers, respectively,
In each of the first and second lens layers, first and second prism mountains arranged adjacent to each other in a band shape along the longitudinal direction are arranged to protrude in a row,
Each of the first and second lens layers has a longitudinal direction perpendicular to each other.
7. The method of claim 6,
A display device in which a fourth support layer is positioned between the second lens layer and the light-diffusing adhesive.
6. The method of claim 5,
The diffusion unit includes a third support layer and first and second diffusion layers on both sides of the third support layer.
6. The method of claim 5,
A light source is positioned under the composite optical sheet,
The light source is arranged along one edge of the light guide plate, or a plurality of display devices arranged under the composite optical sheet.
The method of claim 1,
The display panel includes first and second electrodes and a light emitting diode,
A display device in which the polarizing plate is attached to one side of the display panel through the light-diffusing adhesive. The method of claim 1,
The display device according to claim 1, further comprising a backlight unit positioned on one side of the light-diffusing adhesive and including a light source.
9. The method of claim 8,
The first diffusion layer includes a first bead, the second diffusion layer includes a second bead and is located between the third support layer and the first light collecting part,
The first bead has a uniform size, and the second bead has a different size from each other.

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