KR20170025803A - Composite sheet for changing viewing angle and display device using the same - Google Patents

Abstract

The present invention provides composite sheet for changing a viewing angle and a display device using the same. The composite sheet includes: an electrically conductive lower substrate and an upper substrate; a light direction adjusting layer which is disposed between the lower substrate and the upper substrate and in which anisotropic molecules are dispersed in a binder resin; and a partition wall layer which is laminated on one side of the lower substrate or the upper substrate and includes a pattern in which a dark region for blocking or absorbing light and a bright region for transmitting light alternate with each other. The composite sheet of the present invention and the display device using the same can easily adjust a viewing angle magnification mode and a reduction mode electrically according to the choice of a user while minimizing luminance reduction.

Description

Technical Field [0001] The present invention relates to a composite sheet for adjusting viewing angle and a display device using the composite sheet,

The present invention relates to a composite sheet for viewing angle control and a display device using the composite sheet. More particularly, the present invention relates to an integrated composite sheet in which a polymer dispersed liquid crystal layer containing a dye and a polymer partition wall are interposed between an upper plate and a lower plate electroconductive substrate, The present invention relates to a composite sheet for adjusting a viewing angle and a display device using the composite sheet, which can easily adjust a viewing angle enlarging mode and a reduction mode electrically according to a user's selection while minimizing luminance reduction when applied to a liquid crystal display device.

As the use of the information transmission medium causes private information to be protected in public places, there is a growing demand for a display device capable of recognizing images only within a narrow range of angles by reducing the viewing angle. Particularly, as the information age progresses rapidly, in accordance with the spread of mobile devices such as notebook PC, PMP, and mobile phone, in response to increasing market demand for personal information protection function, an attachable narrow viewing angle filter or a liquid crystal polarization technique It is a situation that various technologies and products are introduced.

However, there are two disadvantages of the attachable narrow viewing angle filter which is distributed in the market. First, after attaching to the front of the display device, it is possible to protect personal information by fixing with a narrow viewing angle. However, when it is desired to disclose information to a plurality of people, it is inconvenient to remove the attached narrow angle of view filter. When the second narrow viewing angle filter is attached to the front surface of the display device, there is a tendency to adversely affect not only the brightness on the side but also the brightness on the front side, and thus the visibility of the image on the front side is deteriorated. Also, there is a disadvantage in a viewing angle control technique using only liquid crystal. First, when only liquid crystal is used, a liquid crystal alignment process is required to form the liquid crystal direction. In addition, a substrate capable of orientation such as glass is required on the upper and lower sides for orientation and a process for joining the glass is required, thereby increasing the number of processes for production.

In order to solve the above-described drawbacks, a process is simplified, and a function of being able to adjust the wide viewing angle and the narrow viewing angle without being limited in time and space is required.

Several methods are known for providing a display that can be switched between the open mode of the wide viewing angle and the secret mode of the narrow viewing angle. Although these methods are specifically described in Korean Patent Laid-Open Publication No. 10-2008-0001971, Korean Patent Laid-Open Publication No. 10-2008-0097752, and Korean Patent Laid-Open Publication No. 10-2014-0064220, It is difficult to control the narrow viewing angle and the wide viewing angle because the structure is complicated and the attachment type privacy filter is required to control the narrow viewing angle and the wide viewing angle.

However, when a composite sheet in which a layer formed by phase separation of molecules having a dielectric constant and an anisotropic refractive index and a partition wall layer is integrated between an upper and a lower plate electroconductive substrate is applied to a liquid crystal display device, The display can be switched between the open mode of the viewing angle and the secret mode of the narrow viewing angle. The inventor of the present invention studied the related art to implement the proposed method, and completed the present invention.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display device capable of easily adjusting a viewing angle enlargement mode and a reduction mode in accordance with a user's selection while minimizing a luminance reduction and thereby controlling a viewing angle Thereby providing a composite sheet.

Another object of the present invention is to provide a display device using the composite sheet.

In the present invention, an electrically conductive lower substrate and an upper substrate; A light direction adjusting layer which is located between the lower substrate and the upper substrate and in which anisotropic molecules are dispersed in the binder resin; And a partition wall layer laminated on one surface of the lower plate substrate or the upper plate substrate and including a pattern in which a dark region capable of blocking or absorbing light and a bright region transmitting light alternately cross each other, Sheet.

Wherein the anisotropic molecule is a molecule having an anisotropic permittivity and an anisotropic refractive index, the difference between the refractive index of the short axis and the refractive index of the binder resin when the voltage is not applied is 0.13 to 0.3; The difference between the refractive index of the short axis when the voltage is applied and the refractive index of the binder resin is 0.0 to 0.07; .

The anisotropic molecule is at least one of the compounds represented by the following general formula (1)

[Chemical Formula 1]

Wherein R is an integer from 2 to 5; C1-C10 alkyl or alkoxy; A is a halogen, a cyano group or an isocyanate group.

For example, the binder resin may be at least one selected from the group consisting of an acrylic resin, a urethane resin, a polyester resin, a urethane acrylic resin, a polyester acrylic resin, a silicone resin and a fluorine resin.

The content of anisotropic molecules in the composition forming the light direction control layer is preferably 10 to 50% by weight.

The thickness of the light direction adjusting layer is preferably 5 to 50 mu m.

It is preferable that the material forming the bright region of the partition wall layer has a difference in refractivity value from the short axis refractive index of the anisotropic molecule in the composition forming the light direction control layer is 0.05 or less.

It is preferable that the difference in refractive index between the binder resin in the composition forming the light direction control layer and the refractive index is 0.05 or less.

The material forming the bright region of the partition wall layer and the binder resin in the composition forming the light direction control layer may be formed of the same polymeric resin material.

The width of the dark region is 1 to 15 mu m; The bright region may have a width of 70 to 150 占 퐉 or a width of a double spacing of 4 to 100 占 퐉 and 70 to 150 占 퐉.

Preferably, the electrically conductive lower substrate and the upper substrate are formed by applying an electrically conductive material on the base film, and the total light transmittance is 90 to 99%, and the electrically conductive layer is disposed toward the optically direction adjusting layer.

The thickness of the electrically conductive lower substrate and the upper substrate is preferably 100 to 200 mu m.

Further, the present invention provides a display device having the above-described composite sheet between a backlight unit and a liquid crystal panel.

The composite sheet for viewing angle control according to the present invention is an integral composite sheet having a structure in which a polymer dispersed liquid crystal layer containing a dye and a polymer partition wall are internalized between an upper plate and a lower plate electroconductive substrate. Therefore, when the liquid crystal display device is applied to the liquid crystal display device, the viewing angle magnification mode and the reduction mode can be electrically adjusted easily according to the user's selection while minimizing the luminance reduction.

1 is a schematic cross-sectional view of a composite sheet for viewing angle control according to the present invention.
2 is a schematic perspective view of a partition wall layer 14 applied to the composite sheet 10 for viewing angle adjustment of the present invention.
3 is a schematic view for explaining an aspect of using the composite sheet for controlling the viewing angle according to the present invention.

Hereinafter, the composite sheet for adjusting the viewing angle according to the present invention will be described in more detail with reference to the drawings.

1 is a schematic cross-sectional view of a composite sheet for viewing angle control according to the present invention. 1, the composite sheet 10 for controlling viewing angle of the present invention comprises an electrically conductive lower substrate 11 and an upper substrate 12; A light direction adjusting layer (13) located between the lower substrate base (11) and the upper substrate base (12) and in which anisotropic molecules (131) are dispersed in the binder resin (132); And a partition wall layer (11) or a partition wall layer (12) which is laminated on one surface of the lower substrate (11) or the upper substrate (12) and includes a pattern in which a dark region capable of intercepting or absorbing light and a bright region 14).

< Lower substrate 11, upper substrate 12>

In the composite sheet 10 for controlling the viewing angle according to the present invention, the lower substrate 11 and the upper substrate 12 serve to support and protect the light direction adjusting layer 13. [

In addition, it functions to apply a voltage to the light direction adjusting layer 13. To this end, the lower substrate 11 and the upper substrate 12 are formed by applying an electrically conductive material on a heat-resistant base film to have an electrically conductive layer, Lt; / RTI &gt;

As the heat-resistant base film, for example, polyester-based or polycarbonate-based polymer films such as polyethylene terephthalate are used and those having a thickness of 20 to 200 μm are used. Examples of the electrically conductive material to be applied on the base film include indium tin oxide, silver nano wire, carbon nano-nube and the like, and the applied thickness is usually 1000 nm or less.

On the other hand, the total light transmittance of the lower substrate base and the upper substrate base is preferably 90 to 99%.

&Lt; Light control layer 13 >

In the light control layer 13, anisotropic molecules 131 are dispersed in the binder resin 132. The anisotropic molecule refers to a molecule having anisotropic refractive index and anisotropic permittivity.

The anisotropic molecule preferably has a difference between the refractive index of the short axis and the refractive index of the binder resin when the voltage is not applied is 0.13 to 0.3; The difference between the refractive index of the short axis when the voltage is applied and the refractive index of the binder resin is 0.0 to 0.07; .

In the present invention, the anisotropic molecule satisfying the above characteristic is a compound represented by the following formula (1)

[Chemical Formula 1]

Wherein R is an integer from 2 to 5; C1-C10 alkyl or alkoxy; A is a halogen, a cyano group or an isocyanate group.

Examples of the above compounds include the following compounds, and all of the compounds exemplified below are commercially available.

(1-1)

(1-2)

(1-3)

(1-4)

(1-5)

The binder resin is a UV curable or thermosetting resin. For example, the binder resin is selected from the group consisting of an acrylic resin, a urethane resin, a polyester resin, a urethane acrylic resin, a polyester acrylic resin, a silicone resin and a fluorine resin Lt; / RTI &gt;

The dispersion of the anisotropic molecules may preferably be a sea-island shape in which the anisotropic molecules 131 are dispersed in the matrix resin 132 in a domain. The sea-island dispersion state can be obtained by, for example, applying a composition obtained by mixing an anisotropic molecule 131 and a UV curable or thermosetting resin onto an electrically conductive lower substrate 11, laminating the upper substrate 12, Can be obtained by inducing phase separation.

The content of anisotropic molecules in the composition forming the light direction control layer is preferably 10 to 50% by weight. If the content of the anisotropic molecule is less than 10% by weight, there is no difference in the refractive index from the resin and the scattering of light becomes weak to form a wide viewing angle. When the content of the anisotropic molecule is more than 50% by weight, There is a problem that the substrate is not supported.

The thickness of the light direction adjusting layer 13 is preferably 5 to 50 탆. If it is less than 5 mu m, it has no optical direction control function, and if it is more than 50 mu m, high current is required for the behavior of the anisotropic molecule.

&Lt; Partition wall layer 14 >

2 is a schematic perspective view of a partition wall layer 14 applied to the composite sheet 10 for viewing angle adjustment of the present invention. Referring to FIG. 2, the barrier rib layer 14 includes a pattern in which a dark region 141 capable of blocking or absorbing light and a bright region 142 capable of transmitting light alternate with each other.

The barrier rib layer can be formed, for example, by coating and curing a composition containing a black dye or a pigment on a transparent plastic substrate.

At this time, the width of the dark region is preferably 1 to 15 mu m. If the width is less than 1 탆, the light can not be blocked from being transmitted, and therefore, the straightness of light can not be formed. If the width exceeds 15 탆, the dark area is widened.

On the other hand, the bright region has a width of 70 to 150 mu m; Or may have a width of double spacing of 4 to 100 mu m and 70 to 150 mu m.

The material forming the bright region of the partition wall layer is such that the refractive index value thereof is not greater than 0.05 with respect to the short axis refractive index of the anisotropic molecule in the composition forming the light direction adjusting layer; The difference between the refractive index of the binder resin and the refractive index of the binder resin in the composition for forming the light direction control layer is preferably 0.05 or less. When the refractive index difference of the material forming the bright region of the barrier rib layer exceeds 0.05, there is a problem that the transmittance is reduced due to the refractive index difference between the bright region and the anisotropic molecule due to the refractive index difference.

&Lt; Function and use sun &

3 is a schematic view for explaining an aspect of using the composite sheet for controlling the viewing angle according to the present invention. Referring to FIG. 3, the composite sheet 10 for controlling the viewing angle according to the present invention is used in the form of being mounted between a backlight unit (BLU) and a liquid crystal panel in a display device.

When a voltage is applied, the light emitted from the backlight unit passes through the integrated composite sheet for viewing angle control, and the molecules having anisotropic permittivity and anisotropic refractive index are oriented along the electric field formed by voltage application, and the difference in refractive index between the polymer and the polymer decreases . As a result, scattered light transmitted through the linearly polarized light passing through the barrier rib layer is decreased, and the side light amount is decreased and the front light amount is increased.

On the other hand, when the voltage is not applied, that is, when the electric field disappears, molecules having anisotropic permittivity and anisotropic refractive index lose directionality, and the refractive index and the difference with respect to the polymer are increased. As a result, linear light passing through the partition wall is scattered, As a result, the side light amount increases and the viewing angle increases. Therefore, it is possible to protect individual information according to time and place through the conversion of the narrow angle of view and the wide viewing angle according to the electric ON / OFF switching of the integral composite sheet.

INDUSTRIAL APPLICABILITY The composite sheet for adjusting the viewing angle of the present invention can be applied to various display devices such as a notebook PC, a mobile phone, and a mobile phone, thereby easily responding to a strong market demand for a personal information protection function.

Hereinafter, the present invention will be described in more detail with reference to Examples. This is for further illustrating the present invention, and the scope of the present invention is not limited to these examples.

< Example  1>

15% by weight of an anisotropic molecule (1-1) having a refractive index of 1.52 and 85% by weight of a urethane acrylic resin having a refractive index of 1.71 as a UV-curable resin was mixed with a polyethylene terephthalate film (ITO) On the ITO surface of the lower substrate deposited to a thickness of 100 nm and then the ITO surface of the top substrate was also coated on the composition and then cured to form a light control layer having a thickness of 10 mu m.

Thereafter, the barrier ribs were laminated on the lower substrate surface to produce a composite sheet for viewing angle control. The barrier ribs were patterned so that the dark region and the bright region crossed at a width of 10 mu m and 100 mu m, respectively.

In the case of the barrier ribs, a sheet having a viewing angle of 30 and a transmittance of 75% was formed. The light control sheet and the partition sheet were formed between the backlight unit and the panel.

< Example  2>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.51 and 1.68, respectively.

< Example  3>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.50 and 1.66, respectively.

< Example  4>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.49 and 1.65, respectively.

< Example  5>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.48 and 1.63, respectively.

< Example  6>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.47 and 1.61, respectively.

< Example  7>

The procedure of Example 1 was repeated except that the anisotropic molecule and the binder resin had birefringence ratios of 1.47 and 1.59, respectively.

< Comparative Example  1>

In Example 1, only the backlight unit and the panel except for the light control sheet and the barrier sheet were formed.

< Comparative Example  2>

In Example 1, only the partition walls, the backlight unit and the panel except for the light control sheet were formed.

< Experimental Example >

CR Measure

CR was measured through white and black state ratios by measuring the luminance of the black and white states of the front and side panels (45 degrees) using BM7 (TOPCON) for optical luminance measurement and a motion analyzer.

CR = white / black

division Narrow Viewing Angle Front
CR Narrow viewing angle side
(45 degrees) CR Wide view angle front
CR Wide viewing angle side
(45 degrees) CR Example 1 1630.02 116.86 949.24 333.96 Example 2 1485.44 326.98 1294.5 283.88 Example 3 1440.52 51.59 1116.85 297.06 Example 4 1469.37 44.2 1298.28 251.67 Example 5 1497.09 37.79 1429.33 206.79 Example 6 1391.65 40.11 1424.58 225.09 Example 7 1453.18 44.2 1109.08 248.64 Comparative Example 1 1279.44 394.74 1319.83 416.18 Comparative Example 2 1620.79 35.36 1476.42 35.8

As can be seen in the above table, it was confirmed that the effect of the narrow viewing angle is improved as the difference from the refractive index of the polymer having the same refractive index of molecules having anisotropic refractive index is decreased.

As a result of comparison between the comparative example 2 and the example, it was found that the sheet characteristics combining the light direction adjustment sheet and the partition sheet form a CR similar to a general narrow angle view sheet, and that CR at the wide viewing angle improves due to the light direction adjustment sheet Respectively.

10 .. Composite sheet for adjusting the viewing angle 11 .. Lower plate substrate
12. Top plate base 13.
131 .. Anisotropic Molecule 132 .. Matrix Resin
14.

Claims (14)

An electrically conductive lower substrate and an upper substrate;
A light direction adjusting layer which is located between the lower substrate and the upper substrate and in which anisotropic molecules are dispersed in the binder resin; And
And a partition wall layer laminated on one surface of the lower plate substrate or the upper plate substrate and including a pattern in which a dark region capable of intercepting or absorbing light and a bright region transmissive to light alternately cross each other, . The method of claim 1, wherein the anisotropic molecule is a molecule having an anisotropic permittivity and an anisotropic refractive index,
The difference between the refractive index of the short axis when the voltage is not applied and the refractive index of the binder resin is 0.13 to 0.3;
The difference between the refractive index of the short axis when the voltage is applied and the refractive index of the binder resin is 0.0 to 0.07; Wherein the composite sheet is a composite sheet. The composite sheet according to claim 1, wherein the anisotropic molecule is at least one compound represented by the following formula (1)
[Chemical Formula 1]

Wherein R is an integer from 2 to 5; C1-C10 alkyl or alkoxy; A is a halogen, a cyano group or an isocyanate group. The composite sheet according to claim 1, wherein the binder resin is at least one selected from the group consisting of an acrylic resin, a urethane resin, a polyester resin, a urethane acrylic resin, a polyester acrylic resin, a silicone resin and a fluorine resin. The composite sheet according to claim 1, wherein the content of anisotropic molecules in the composition forming the light direction control layer is 10 to 50% by weight. The composite sheet according to claim 1, wherein the thickness of the light direction adjusting layer is 5 to 50 占 퐉. The composite sheet according to claim 1, wherein the material forming the bright region of the partition wall layer has a difference in refractivity value from a short axis refractive index of the anisotropic molecule in the composition forming the light direction control layer is 0.05 or less. The composite sheet according to claim 1, wherein the material forming the bright region of the partition wall layer is a difference between a refractive index and a binder resin in the composition forming the light direction control layer is 0.05 or less. The composite sheet according to claim 8, wherein the material forming the bright region of the partition wall layer and the binder resin in the composition forming the light direction control layer are formed of the same polymeric resin material. The composite sheet according to claim 8, wherein the width of the dark region is from 1 to 15 mu m. 9. The method of claim 8, wherein the bright region is 70 to 150 mu m wide; Or a double spacing of 4 to 100 占 퐉 and 70 to 150 占 퐉. [3] The method of claim 1, wherein the electrically conductive lower substrate and the upper substrate are formed by applying an electrically conductive material on a substrate film, wherein the total light transmittance is 90 to 99% . The composite sheet according to claim 1, wherein the thickness of the electrically conductive lower plate substrate and the top plate substrate is 100 to 200 占 퐉. A display device comprising the composite sheet of claim 1 between a backlight unit and a liquid crystal panel.

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