KR20210003655A - Light Control Film Having Nano Light Absorbing Layer And Display Using The Same - Google Patents

Abstract

The present invention relates to a light control film implemented with a nano light absorption layer which does not lower luminance of a display panel, and a display device using the same. According to the present invention, the light control film comprises a lower layer, an upper layer, an intermediate layer, and the nano light absorption layer. The lower layer is disposed on a plane consisting of a first axis and a second axis. The upper layer has the same shape as the lower layer and is disposed opposite to each other. The intermediate layer has a certain thickness and is interposed between the lower layer and the upper layer. The nano light absorption layer has a predetermined width on the first axis, a predetermined length on the second axis, and a height corresponding to the thickness of the intermediate layer. The plurality of nano light absorption layers are disposed at regular intervals along the first axis in the intermediate layer. The ratio of an arrangement interval to the width of the nano light absorption layer has a value selected from 10 : 1 to 20 : 1.

Description

Light Control Film Having Nano Light Absorbing Layer And Display Using The Same}

This application relates to a light control film implemented with a nano light absorbing layer and a display device using the same. In particular, it relates to a light control film for narrowly controlling the viewing angle of a display device in a specific direction.

Recently, various types of display devices such as CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), PDP (Plasma Display Panel), and electroluminescent devices (Luminescent Display) have been developed and developed. Such various types of display devices are used to display image data of various products such as computers, mobile phones, bank deposit and withdrawal devices (ATM), and vehicle navigation systems according to their respective characteristics.

The display device displays image information desired by the user. It is generally developed to have a wide viewing angle in order to allow a user to view an image of a display device from various angles. However, if the viewing angle of each individual product to which the display device is applied may have a wide viewing angle, the characteristics of the product may be adversely affected, and thus a narrow viewing angle is required.

For example, in the case of a bank deposit and withdrawal device (ATM), when a user inputs personal information, it is more desirable to have a narrow viewing angle of the display device because it is required to prevent other people around the user from recognizing personal information. In addition, in the case of a vehicle navigation system, when the viewing angle of the display device is wide, light is reflected on the windshield of the vehicle when driving at night, thereby adversely affecting the driver's safe driving. In addition, in the case of a computer or a mobile phone, even when the user does not want the privacy to be exposed, the wide viewing angle of the display device is contrary to the user's request.

It is necessary to design and manufacture the display device itself by adjusting the viewing angle appropriate for the field to which the display device is applied. However, if the display device is separately manufactured according to the product requirements, productivity is degraded. Accordingly, after manufacturing a display device having a wide viewing angle, a method of narrowing the viewing angle according to the applied field has been devised. In response to the demands of this situation, a light control film has been developed that can be attached to a display surface of a display device to narrow the viewing angle.

The light control film proposed so far has a problem in that the brightness of the display device is deteriorated due to its low precision. In addition, when external light reflection is severe, when the brightness of the display device is dark, it may be difficult to accurately recognize image information of the display device. Accordingly, there is an increasing demand for a highly precise light control film having a new structure.

The purpose of this application is to overcome the problems of the prior art, and to provide a light control film and a display device having the same to adjust a viewing angle without lowering the luminance of the display device due to high precision. Another object of this application is to provide a light control film and a display device including the same, which prevents light from outside the display device from being reflected off the surface of the display device and does not deteriorate display quality.

In order to achieve the above object, the light control film according to this application includes a lower layer, an upper layer, an intermediate layer, and a nano light absorbing layer. The lower layer is disposed on a plane consisting of a first axis and a second axis. The upper layer has the same shape as the lower layer and is disposed to face each other. The intermediate layer has a certain thickness and is interposed between the lower layer and the upper layer. The nano light absorbing layer has a predetermined width on a first axis, a predetermined length on a second axis, and a height corresponding to the thickness of the intermediate layer. A plurality of nano light absorbing layers are disposed at regular intervals along the first axis in the intermediate layer. The ratio of the arrangement interval to the width of the nano light absorbing layer has a value selected from 10:1 to 20:1.

For example, the width of the nano light absorbing layer has a value selected from 0.1 μm to 1.0 μm.

For example, the ratio of the arrangement interval to the height of the nano light absorbing layer has a value selected from 1:1 to 1:4.

For example, the lower layer, the middle layer, and the upper layer have a higher refractive index than air.

For example, in one nano light absorbing layer, at least two or more thin film layers are stacked.

For example, the width of one thin film layer included in the nano light absorbing layer has a value selected from 0.01 μm to 0.1 μm.

For example, in one nano light absorbing layer, a first thin film layer and a second thin film layer are stacked on each other. The first thin film layer has a first reflectance. The second thin film layer has a second reflectance different from the first reflectance.

For example, one nano light absorbing layer further includes a third thin film layer having a third reflectance different from the first reflectance and the second reflectance.

For example, in one nano light absorbing layer, a first thin film layer having a first transmittance and a second thin film layer having a second transmittance different from the first transmittance are stacked on each other.

For example, one nano light absorbing layer further includes a third thin film layer having a third transmittance different from the first transmittance and the second transmittance.

As an example, the plurality of nano light absorbing layers includes a first nano light absorbing layer and a second nano light absorbing layer adjacent to each other at an arrangement interval. The intermediate layer includes a lower prism portion disposed at a lower portion and an upper prism portion disposed at an upper portion based on an inclined surface connecting the lower end of the second nano light absorbing layer from the upper end of the first nano light absorbing layer.

For example, the lower prism portion has a first refractive index. The upper prism portion has a second refractive index smaller than the first refractive index.

For example, the upper layer, the lower layer, and the intermediate layer include a transparent organic material. The nano light absorbing layer includes a material that absorbs visible light.

For example, the nano light absorbing layer is disposed at an angle inclined in one direction based on the normal line of the surface of the light control film.

For example, the nano light absorption layer has a refractive index smaller than that of the upper layer, the lower layer, and the intermediate layer.

For example, the upper layer, the lower layer, and the lower prism portion have the same refractive index. The upper prism portion has a lower refractive index than the lower prism portion. The nano light absorbing layer has a refractive index lower than that of the upper prism portion and the lower prism portion.

For example, one direction in which the nano light absorbing layer is inclined is a direction in which the upper end of the nano light absorbing layer is inclined toward the upper prism.

Further, the display device according to this application includes a substrate, a display layer, an encapsulation layer, a quarter wave plate, a cover substrate, and a light control film. A plurality of pixel regions are defined on the substrate. The display layer includes driving elements and light-emitting elements disposed on the substrate to correspond to the pixel regions. The sealing layer covers the display layer. The quarter wave plate is disposed on the sealing layer. The cover substrate is disposed on the quarter wave plate. The light control film is disposed on the cover substrate. The light control film includes a lower layer, an upper layer, an intermediate layer, and a nano light absorbing layer. The lower layer is disposed on a plane consisting of a first axis and a second axis. The upper layer has the same shape as the lower layer and is disposed to face each other. The intermediate layer has a certain thickness and is interposed between the lower layer and the upper layer. The nano light absorbing layer has a predetermined width on a first axis, a predetermined length on a second axis, and a height corresponding to the thickness of the intermediate layer. A plurality of nano light absorbing layers are disposed at regular intervals along the first axis in the intermediate layer. The ratio of the arrangement interval to the width of the nano light absorbing layer has a value selected from 10:1 to 20:1.

This application has a structure in which a plurality of nano-unit thin light-absorbing thin film layers are arranged at regular intervals, and the arrangement interval is 10 times or more of the thickness of the light absorbing thin film layer. Therefore, the light control film according to this application can secure an aperture ratio of 90% or more, and when applied to a display panel, the luminance of the display panel is not lowered. In addition, by configuring the nano-unit thin film layer as a plurality of thin-film layers having different refractive indices or different absorption coefficients, even if the thickness of the thin film has a nano-unit value, excellent light absorption is secured, thereby providing a light control film with excellent viewing angle control. Can be implemented. In addition, since the structure in which a plurality of nano-unit light absorbing thin film layers are continuously arranged can have linear polarization performance, it provides a function of preventing reflection of external light. Moreover, it is possible to provide a display panel having a function of reflecting external light and having a thin thickness.

1 is a perspective view showing the structure of a light control film having a nano light absorbing layer according to a first embodiment of this application.
FIG. 2 is a cross-sectional view showing the structure of a light control film including a nano light absorbing layer according to the first embodiment of this application, cut along the perforation line I-I' of FIG. 1.
3A is an enlarged view showing an arrangement structure of a nano light absorbing layer included in the light control film according to the first embodiment of this application.
3B is a schematic diagram illustrating a light path of leakage light absorbed by the nano light absorbing layer in the light control film according to the first embodiment of this application.
4 is an enlarged cross-sectional view showing the structure of a nano light absorbing layer included in the light control film according to the first embodiment of this application.
5A is a cross-sectional view showing the structure of a light control film according to a second embodiment of this application.
5B is a cross-sectional view showing a viewing angle range set by the light control film according to the second embodiment of this application.
6 is a cross-sectional view showing the structure of a light control film according to a third embodiment of this application.
7 is a cross-sectional view showing the structure of a light control film according to a fourth embodiment of this application.
8 is a cross-sectional view showing the structure of a light control film according to a fifth embodiment of this application.
9 is a cross-sectional view comparing viewing angle ranges set by the light control film according to the third to fifth embodiments of this application.
10A to 10E are cross-sectional views illustrating a structure of an electroluminescent display device including a light control film according to each of the first to fifth embodiments of this application.

Advantages and features of this application, and a method of achieving them will become apparent with reference to examples described later in detail together with the accompanying drawings. However, this application is not limited to the examples disclosed below, but will be implemented in a variety of different forms. However, the examples of this application are intended to complete the disclosure of the present application, and are generally It is provided to completely inform the scope of the invention to those skilled in the art, and the invention of this application is only defined by the scope of the claims.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining an example of this application are illustrative, and are not limited to the matters shown here. The same reference numerals refer to the same components throughout the specification. In addition, in describing an example of this application, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the application, the detailed description thereof will be omitted.

When'include','have','consists of' and the like mentioned in this application specification are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise.

In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description.

In the case of a description of the positional relationship, for example, if the positional relationship of two parts is described as'upper','upper of','lower of','next to','right' Or, unless'direct' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, when a temporal predecessor relationship is described as'after','following','after','before', etc.,'right' or'direct' It may also include cases that are not continuous unless this is used.

First, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component from another component. Therefore, the first component mentioned below may be the second component within the technical idea of this application.

The term “at least one” is to be understood as including all possible combinations from one or more related items. For example, the meaning of “at least one of the first item, the second item, and the third item” means 2 among the first item, the second item, and the third item as well as each of the first item, the second item, or the third item. It may mean a combination of all items that can be presented from more than one.

Each of the features of the various examples in this application can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each of the examples can be implemented independently of each other or can be implemented together in an association relationship. .

Hereinafter, an example of a light control film including a nano light absorbing layer and a display device using the same according to this application will be described in detail with reference to the accompanying drawings. In adding reference numerals to elements of each drawing, the same elements may have the same numerals as possible even if they are indicated on different drawings.

<First embodiment>

Hereinafter, a light control film including a nano light absorbing layer according to a first embodiment of this application will be described with reference to the drawings. 1 is a perspective view showing the structure of a light control film having a nano light absorbing layer according to a first embodiment of this application. FIG. 2 is a cross-sectional view showing the structure of a light control film including a nano light absorbing layer according to the first embodiment of this application, cut along the perforation line I-I' of FIG. 1.

1 and 2, the light control film (LCF) having a nano light absorbing layer according to the first embodiment of this application includes a lower layer 100, an upper layer 200, an intermediate layer 300, and a nano light absorbing layer ( 500). The lower layer 100 may have a plate-like structure having a constant first thickness t1. The upper layer 200 may have the same shape as the lower layer 100 and may have a constant second thickness t2. The first thickness t1 and the second thickness t2 may be the same. The lower layer 100 and the upper layer 200 are opposed to each other at a predetermined distance, and the intermediate layer 300 is filled therebetween.

The light control film (LCF) is an optical functional film having a function of emitting incident light only within a certain angle range. Accordingly, the lower layer 100, the upper layer 200, and the intermediate layer 300 may include a transparent organic material. For example, it may include at least one of organic materials such as acrylic resin material, polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyacrylate, polyurethane, polycarbonate, polypropylene, and the like.

On the other hand, it is preferable that the nano light absorbing layer 500 has a property of absorbing light. For example, it may include a metal material, a metal oxide material, a nitride material, or an opaque material such as a carbon allotrope. Specifically, silicon nitride (SiN), titanium nitride (TiN), silicon carbide (SiC), tantalum (Ta), titanium (Ti), tungsten (W), nickel (Ni), copper oxide (CuO), aluminum oxide It may include any one selected from (Al ₂ O ₃ ), iron oxide (Fe ₃ O ₄ ), nickel oxide (NiO), and tantalum oxide (Ta ₂ O ₅ ). Alternatively, the nano light absorbing layer 500 may be formed of a carbon allotrope such as graphene, carbon nanotubes, or fullerene. In addition, the nano light absorbing layer 500 may be formed of an organic material having excellent light absorption.

Referring to FIG. 1, the lower layer 100 has a plate-like structure disposed on a plane consisting of an X-axis and a Y-axis. The upper layer 200 has the same shape as the lower layer 100 and is opposed to each other by being spaced a certain distance along the Z axis. The intermediate layer 300 is interposed between the lower layer 100 and the upper layer 200 and may have a predetermined thickness T on the Z axis.

The nano light absorbing layer 500 has a width W having a value in nano units on the X axis, a length L along the Y axis, and a height H corresponding to the thickness T of the intermediate layer 300. A plurality of nano light absorbing layers 500 are disposed in the intermediate layer 300 along the X-axis at predetermined intervals G. In particular, the ratio of the width W of the nano light absorbing layer 500 to the arrangement interval G of the nano light absorbing layers 500 may have any one selected from 10:1 to 20:1.

For a specific example, the lower layer 100 and the upper layer 200 may have a rectangular plate-like structure having a length a and a width b and a first thickness t1 and a second thickness t2, respectively. The intermediate layer 300 may have a hexahedral structure disposed between the lower layer 100 and the upper layer 300. For example, the intermediate layer 300 may be a rectangular parallelepiped having a length a, a width b, and a thickness T. The lower layer 100, the intermediate layer 300, and the upper layer 200 may be sequentially stacked.

The nano light absorbing layer 500 has a partition wall structure in which a plurality of nano light absorbing layers 500 are disposed at a predetermined interval G between the lower layer 100 and the upper layer 300. In other words, the nano light absorbing layer 500 has a vertical plate-like structure distributed in the intermediate layer 300 at a predetermined interval G. For example, the nano light absorbing layer 500 may have a thin plate-like structure having a length (L), a height (H), and a width (W). In addition, several nano light absorbing layers 500 may be arranged with a predetermined spacing G.

Here, the length L of the nano light absorbing layer 500 may be the same as the width b of the lower layer 100. In addition, the height H of the nano light absorbing layer 500 may be the same as the thickness T of the intermediate layer 300. It is preferable that the width (W) of the nano light absorbing layer 500 has a thickness in nano units.

For example, it is preferable that the width (W) of the nano light absorbing layer 500 has a value between 0.1 μm and 1.0 μm. In addition, it is preferable that the arrangement interval G in which the nano light absorbing layers 500 are arranged has a value between 1.0 μm and 10.0 μm. In particular, between the arrangement interval G and the width W of the nano light absorbing layer 500 may have a value between 10:1 and 20:1. Accordingly, the transmittance of light penetrating from the lower layer 100 to the upper layer 200 may be ensured at least 95%.

As shown in FIG. 2, when light is irradiated from the surface of the lower layer 100 in the normal direction, some of the light is absorbed by the cross-section of the nano light absorbing layer 500, and only light passing through the intermediate layer 300 is The light is transmitted to the outside of the upper layer 200. In the structure of this application, since the width (W) of the nano light absorbing layer 500 is 1.0 μm, and the arrangement interval (G) is set to be at least 10 times the width (W), the transmittance is 95% or more. Can be secured.

Hereinafter, a viewing angle control mechanism by the nano light absorbing layer 500 included in the light control film (LCF) according to the first embodiment of this application will be described with reference to FIG. 3A. 3A is an enlarged view showing an arrangement structure of a nano light absorbing layer included in the light control film according to the first embodiment of this application.

The light control performance of the light control film (LCF) according to the first embodiment of this application can be determined by the relationship between the arrangement interval (G) of the nano light absorption layer 500 and the height (H) of the nano light absorption layer 500. have. For example, the ratio between the arrangement interval G and the height H of the nano light absorbing layer 500 may be set by selecting any one of values between 1:1 and 1:4. Preferably, the ratio between the arrangement interval (G) and the height (H) may be set by selecting any one of values between 1:2 and 1:3.2. Most preferably, the ratio between the arrangement interval (G) and the height (H) may have a value of 1: 2.6.

The arrangement pitch of the nano light absorbing layer 500 may be defined as the sum of the width W of the nano light absorbing layer 500 and the arrangement gap G. In this application, the width (W) of the nano light absorbing layer 500 is very thin compared to the arrangement interval (G). Accordingly, the ratio between the arrangement interval G and the height H may be understood as a ratio between the arrangement pitch and the height H of the nano light absorbing layer 500.

Referring to FIG. 3A, light is incident on the lower surface of the lower layer 100 from the lower surface of the light control film LCF according to the first embodiment of this application. The light control film (LCF) according to the first embodiment of this application is often adhered to the display panel. Since the display panel bonded to the lower layer 100 has little difference in refractive index, for convenience, the incident light is not refracted and has a path through which it is incident.

In addition, when the lower layer 100, the intermediate layer 300, and the upper layer 200 are made of the same material, since there is no difference in refractive index, the transmitted light passing through the light control film LCF is light extending in a straight straight line parallel to the incident light. Has a path. Meanwhile, the upper layer 200 may be a layer disposed on the outermost side of the display panel including the light control film LCF. In this case, the upper surface of the upper layer 200 is in contact with air. When the refractive index of the upper layer 200 is greater than that of air, the emitted light is refracted in a direction further away from the normal direction of the surface of the upper layer 200.

It will be described in detail with reference to FIG. 3A. The light incident from the lower surface of the light control film LCF may be considered to be incident in a region divided into three regions of the central portion C, the left portion L and the right portion R.

The light incident from the center (C) is again vertically incident light (1000) incident parallel to the normal of the surface of the light control film (LCF), left inclined incident light (1001) incident in the left direction, and right inclined incident light incident from the right direction. It can be classified as (1002). The vertically incident light 1000 is incident on the lower layer 100 along the normal direction, and proceeds as the vertically transmitted light 2000 that passes through the lower layer 100, the intermediate layer 300, and the upper layer 200. Then, it is emitted as vertical emission light 3000 that is emitted outside the light control film LCF.

Most of the light incident between the upper end and the lower end of the nano light absorbing layer 500 among the left inclined incident light 1001 is absorbed by the nano light absorbing layer 500. On the other hand, only light having a radiation angle smaller than the upper end of the nano light absorbing layer 500 out of the incident light 1001 in the left inclination proceeds to the transmitted light in the left inclination 2001 passing through the lower layer 100, the intermediate layer 300 and the upper layer 200 do. The left slanted transmitted light 2001 passes through the upper layer 200 and becomes a left slanted emission light 3001 to be emitted outside the light control film LCF. Since there is an air layer outside the light control film LCF, the left oblique exit light 3001 is refracted in a direction away from the normal direction. That is, the left oblique exit light 3001 has an exit angle θ'inclined from the normal direction to the left direction.

In the same manner, most of the light incident between the upper and lower ends of the nano light absorbing layer 500 among the right inclined incident light 1002 is absorbed by the nano light absorbing layer 500. On the other hand, only the light having a radiation angle smaller than the upper end of the nano light absorbing layer 500 among the right inclined incident light 1002 proceeds to the right inclined transmitted light 2002 passing through the lower layer 100, the intermediate layer 300 and the upper layer 200. do. The right inclined transmitted light 2002 passes through the upper layer 200, becomes a right-inclined emission light 3002, and is emitted outside the light control film LCF. Since there is an air layer outside the light control film LCF, the right-slope exit light 3002 is refracted in a direction away from the normal direction. That is, the right inclined outgoing light 3002 has an outgoing light angle θ'inclined from the normal direction to the right.

Light incident from the left portion L may be further divided into vertically incident light 1000 incident parallel to the normal of the surface of the light control film LCF and right inclined incident light 1002 ′ incident in the right direction. Since the nano light absorbing layer 500 is adjacent to the left side of the left portion R, almost all of the light incident in the left direction is absorbed by the nano light absorbing layer 500, so that the incident light inclined to the left is not considered. The vertically incident light 1000 is incident on the lower layer 100 along the normal direction, and proceeds as the vertically transmitted light 2000 that passes through the lower layer 100, the intermediate layer 300, and the upper layer 200. Then, it is emitted as vertical emission light 3000 that is emitted outside the light control film LCF.

Among the right inclined incident light 1002 ′, most of the light incident between the upper and lower ends of the nano light absorbing layer 500 is absorbed by the nano light absorbing layer 500. On the other hand, only the light having a radiation angle smaller than the upper end of the nano light absorbing layer 500 among the right inclined incident light 1002' passes through the lower layer 100, the intermediate layer 300, and the upper layer 200. Proceed to. The right inclined transmitted light 2002' passes through the upper layer 200, becomes a right-inclined emission light 3002', and is emitted outside the light control film LCF. Since there is an air layer outside the light control film LCF, the right-slope exit light 3002' is refracted in a direction further away from the normal direction. That is, the right inclined outgoing light 3002 ′ has an outgoing light angle θ inclined from a normal direction to a right direction.

The light incident from the right portion R may be further divided into a vertical incident light 1000 incident parallel to the normal of the surface of the light control film LCF and a left oblique incident light 1001 ′ incident in the left direction. Since the nano light absorbing layer 500 is adjacent to the right side of the right part L, almost all light incident in the right direction is absorbed by the nano light absorbing layer 500, so that the incident light inclined right is not considered. The vertically incident light 1000 is incident on the lower layer 100 along the normal direction, and proceeds as the vertically transmitted light 2000 that passes through the lower layer 100, the intermediate layer 300, and the upper layer 200. Then, it is emitted as vertical emission light 3000 that is emitted outside the light control film LCF.

Most of the light incident between the upper end and the lower end of the nano light absorbing layer 500 among the left inclined incident light 1001 ′ is absorbed by the nano light absorbing layer 500. On the other hand, only light having a radiation angle smaller than the upper end of the nano-light absorbing layer 500 among the left-slanted incident light 1001' passes through the lower layer 100, the intermediate layer 300, and the upper layer 200. Proceed to. The left oblique transmitted light 2001 ′ passes through the upper layer 200, becomes a left oblique exit light 3001 ′, and is emitted outside the light control film LCF. Since there is an air layer outside the light control film LCF, the left oblique exit light 3001' is refracted in a direction further away from the normal direction. That is, the left oblique exit light 3001 ′ has an exit angle θ inclined from the normal direction to the left direction.

As a result, the viewing angle θ may be determined by the outgoing light angle θ that determines the traveling direction of the light transmitted through the light control film LCF according to the first exemplary embodiment of this application.

For example, in the light control film, when the arrangement interval (G) and the height (H) of the nano light absorbing layer 500 have a value of 1:1, the viewing angle shielding angle is one based on the nano light absorbing layer 500 It has a value of 45°±5° in the direction. Considering the trigonometric function, the viewing angle is calculated to be 45° in one direction. However, light passes through the light control film (LCF) and is emitted into the air. When the refractive index of the light control film (LCF) has a higher value than that of air, the viewing angle becomes larger by the difference in the refractive index, and thus the light control film (LCF Depending on the refractive index value of ), it may have a range of 45°±5°. Here, for convenience, since the thickness of the lower layer 100 and the upper layer 200 is much thinner than that of the intermediate layer 300, the difference in the optical path due to the thickness of the lower layer 100 and the upper layer 200 is not considered.

As another example, when the arrangement interval (G) and height (H) of the nano light absorbing layer 500 have a value of 1:2, the viewing angle shielding angle is 63.4°± in one direction based on the nano light absorbing layer 500 It has a value of 5°. As another example, when the arrangement interval (G) and height (H) of the nano light absorbing layer 500 have a value of 1:3, the viewing angle blocking angle is 71.5° in one direction based on the nano light absorbing layer 500 It has a value of ±5°.

In addition, when the arrangement interval (G) and height (H) of the nano light absorbing layer 500 have a value of 1:4, the viewing angle shielding angle is 76°±5 in one direction based on the nano light absorbing layer 500 Has a value of °. That is, as the height H has a larger value than the arrangement interval G, the narrower the viewing angle is obtained. By selecting the ratio of the arrangement interval (G) and the height (H) of the nano light absorbing layer 500, it is possible to provide a viewing angle that meets the requirements of the applied product.

As described above, in the first embodiment of this application, a ratio of the most preferable arrangement spacing (G) and height (H) may be 1:2.6. In this case, the viewing angle shielding angle has a value of 68.9°±5° in one direction based on the nano light absorbing layer 500. When this viewing angle is applied to a vehicle navigation system or a head up display (HID), a product that provides the driver with the safest driving environment can be designed.

Hereinafter, a detailed structure of the nano light absorbing layer included in the light control film (LCF) according to the first embodiment of this application will be described with reference to FIG. 4. 4 is an enlarged cross-sectional view showing the structure of a nano light absorbing layer included in the light control film according to the first embodiment of this application.

Referring to FIG. 4, the nano light absorbing layer 500 included in the light control film LCF according to the first embodiment of this application may have a structure in which at least two thin film layers are stacked. For example, a first thin film layer and a second thin film layer made of different materials may be stacked. Alternatively, a first thin film layer, a second thin film layer, and a third thin film layer made of different materials may be successively stacked. Furthermore, n different thin film layers may be continuously stacked.

One of the plurality of thin film layers forming one nano light absorbing layer 500 may have a width of 0.01 μm to 0.1 μm. As such, one nano light absorbing layer 500 in which thin film layers having a width of nano units are stacked may have a width of less than 1.0 μm. Here, the'width' of the nano light absorbing layer 500 is a name named in consideration of the direction on the drawing, and may be referred to as'thickness' in another expression.

Since the width of the nano light absorbing layer 500 is very thin in nano units, the absorption rate indicating the ability to block light incident to the side may be low. In order to secure the light blocking performance of the nano light absorbing layer 500, it is preferable to use a material having a high absorption rate.

For example, by alternately stacking metal materials, metal oxide materials, or nitride materials having different reflectances in consideration of productivity and material cost, the nanometal 500 having increased light absorption may be formed. For example, when forming the nano light absorbing layer 500 as a multilayer thin film layer, one thin film layer is silicon nitride (SiN), titanium nitride (TiN), silicon carbide (SiC), tantalum (Ta), titanium (Ti), Nickel (Ni), tungsten (W), copper oxide (CuO), aluminum oxide (Al ₂ O ₃ ), iron oxide (Fe ₃ O ₄ ), nickel oxide (NiO), and tantalum oxide (Ta ₂ O ₅ ). It can contain either.

For example, the nano light absorbing layer 500 may form a multilayer structure using nickel, which is a metallic material. The nano light absorbing layer 500 may be formed by sequentially stacking a first nickel metal layer, a nickel oxide layer, and a second nickel metal layer.

As another example, the nano light absorbing layer 500 may include a non-metallic material such as a carbon allotrope. The carbon allotrope is made of carbon, but it refers to a substance with different properties due to the different arrangement light structure of the atoms. The carbon allotrope may include fullerene, graphene, or carbon nanotubes. For example, the fullerene may include C60 fullerene composed of fullerene molecules composed of 60 carbon atoms, C70 fullerene composed of fullerene molecules composed of 70 carbon atoms, or C76 fullerene composed of fullerene molecules composed of 76 carbon atoms.

The optical properties of a material are divided into reflection, transmission and absorption. That is, when light is incident on a material layer, as shown in Equation 1 below, some are reflected, some are absorbed, and the rest are transmitted.

[Equation 1]

Incident light (I) = reflectance (R) + absorption (A) + transmittance (T) = 100%

As described above, the use of a material with a high absorption rate is most preferable for designing the nano light absorption layer.

For example, in the case of a metallic material, the reflectance of light is 90% or more. When light enters the metal layer, electrons are excited above the Fermi level, absorbing all light energy, and immediately emitted as photons. It is recognized that light is reflected because such light absorption and energy emission occur almost simultaneously. The remaining 10% is absorbed or transmitted through the metal layer.

This light absorption and photon emission are usually within 0.1 μm. Therefore, in the case of a metal layer having a thickness of several tens of nm, most of the light is transmitted. That is, when light is irradiated to the nano metal layer, it may have the highest transmittance ratio in Equation 1. For example, when light is irradiated on a metal layer of several tens of nm, 80% or more is transmitted, 10% is reflected, and 10% can be absorbed.

By applying these properties, when metal materials having different reflectances are stacked in nano-level multilayers, a large amount of transmitted light can be repeatedly reflected and re-reflected at the interface of the multilayer thin films. As a result, it is trapped inside the entire metal layer and is absorbed as thermal energy while resonating, thereby increasing the absorption rate. In addition to the metal material, this mechanism may be the same for the inorganic material thin film described above. In addition, such a mechanism may be expected in a specific organic material thin film, but in the case of an organic material, a nano light absorbing layer having a high absorption rate may be formed by stacking a material having a high absorption rate in multiple layers.

Specifically, as shown in (a) of FIG. 4, by alternately stacking a first thin film layer 5a having a first reflectance and a second thin film layer 5b having a second reflectance, nano light An absorption layer 500 may be formed. As another example, as shown in FIG. 4B, a first thin film layer 5a having a first reflectance, a second thin film layer 5b having a second reflectance, and a third thin film layer 5c having a third reflectance The nano light absorbing layer 500 may be formed by sequentially stacking them. Alternatively, the nano light absorbing layer 500 may be formed by sequentially stacking n thin film layers having different reflectances.

In FIG. 4, the first to third thin film layers 5a to 5c have been described only in the case of stacking thin film layers having different reflectances in the previous example, but as can be seen from Equation 1, depending on the optical properties of the material used, It can also be set in consideration of water absorption or transmittance. That is, the nano light absorption layer 500 may be formed by stacking thin film layers having different transmittances or different absorption rates.

In this way, by adjusting the structure of the nano light absorbing layer 500 to secure the light absorption rate of the nano light absorbing layer 500 to 90% or more, the reflectance may be set to less than 10%. That is, as shown in FIG. 3B, only an amount of less than 10% of the light incident toward the nano light absorbing layer 500 may be reflected.

The reflected light may have a larger outgoing angle θ" than the viewing angle θ as shown in the light path shown in Fig. 3B. However, since the amount of light is less than 10%, the leakage light perceived beyond the viewing angle θ 3B is a schematic diagram illustrating a light path of leakage light absorbed by the nano light absorbing layer 500 in the light control film (LCF) according to the first embodiment of this application.

Referring to FIG. 3B, when light incident toward the nano light absorbing layer 500 on one side is reflected among the light incident from the lower part of the light control film (LCF), a large amount of light is at the upper end of the nano light absorbing layer 500 on the opposite side. It can be out of the way. These lights have an outgoing light angle (θ") greater than the viewing angle (θ). However, the nano light absorption layer 500 provided in the light control film (LCF) according to this application has a light absorption rate of 90% or more. Accordingly, the amount of reflected light can be minimized.

For example, among the incident lights incident on the lower layer 100 from the left region L, the optical path of the right inclined incident light 1002' incident toward the left nano light absorbing layer 500 is examined. The right inclined incident light 1002 ′ reaches the nano light absorbing layer 500 as the right inclined projection light 2002 ′ passing through the lower layer 100 and the intermediate layer 300. Thereafter, it is reflected and proceeds through the intermediate layer 300 and the upper layer 200 as the left oblique reflected light 2002". After that, the left oblique exit light 3002' is emitted to the outside of the light control film LCF. The upper layer 200 is in contact with the air having a small refractive index, and the left inclined outgoing light 3002' is refracted in a direction away from the normal direction, that is, the left inclined outgoing light 3002' by reflected light is at the viewing angle of the reflected light. θ"), which has an angular value greater than the viewing angle θ described in FIG. 3A. Here, the arrow indicated by the dotted line is the left oblique exit light 3001' described in FIG. 3A, and determines the left viewing angle θ.

Accordingly, light leaking outside the narrow viewing angle θ may be generated by the reflected light. Of course, since the light absorption rate of the nano light absorption layer 500 is adjusted to 90% or more, the amount of light leaked is very small. However, in a specific display device, even a small amount of light may cause inconvenience to the user. Hereinafter, a structural feature capable of further reducing or completely removing light leaking outside a narrow viewing angle will be described.

<Second Example>

Hereinafter, a second embodiment of this application will be described with reference to FIGS. 5A and 5B. 5A is a cross-sectional view showing the structure of a light control film according to a second embodiment of this application. 5B is a cross-sectional view showing a viewing angle range set by the light control film according to the second embodiment of this application. The light control film LCF of FIG. 5A has almost the same structure as the light control film LCF of FIG. 2. If there is a difference, the intermediate layer 300 has a lower prism portion (Pa) disposed below the hypotenuse 501 (or inclined surface) connecting the diagonal points of the adjacent nano light absorbing layers 500 between the nano light absorbing layers 500. ) And the upper prism portion (Pb) disposed on the upper portion is further provided.

The lower prism part Pa may include the same material as the lower layer 100 and the upper layer 200, and a transparent organic material. In this case, the lower prism portion Pa may have the same refractive index as the lower layer 100 and the upper layer 200.

Meanwhile, the upper prism portion Pb may include a transparent organic material different from the lower prism portion Pa. In this case, the upper prism portion Pb may have a lower refractive index than the lower layer 100 and the upper layer 200. As an example, the refractive index of the upper prism part Pb may have a value lower than the refractive index of the lower prism part Pa by 0.05 to 0.1. For example, the upper prism part Pb may have a refractive index of 1.40, and the lower prism part Pa may have a refractive index of 1.45. As another example, the upper prism portion Pb may have a refractive index of 1.40, and the lower prism portion Pa may have a refractive index of 1.50.

In the case of such a structure, when light incident from the lower layer 100 passes through the intermediate layer 300 and the upper layer 200 and is emitted to the outside, it has a different light path than that of FIG. 2. Referring to FIG. 5A, light is incident on the lower surface of the lower layer 100 from the lower surface of the light control film LCF according to the second embodiment of this application. The light control film (LCF) according to the second embodiment of this application is often adhered to the display panel. Since the display panel bonded to the lower layer 100 has almost no difference in refractive index, for convenience, the incident light 1000 is illustrated as having a path through which it is incident without being refracted. In addition, in the second embodiment, since the hypotenuse 501, which is the boundary between the lower prism portion Pa and the upper prism portion Pb, is inclined from the upper right to the lower left, it mainly affects the light incident toward the hypotenuse 501. Can give Accordingly, in the second embodiment, a description will be given centering on the incident light inclined right.

In addition, when the lower prism portion Pa of the lower layer 100 and the intermediate layer 300 is made of the same material, since there is no difference in refractive index, the first transmitted light 2001 traveling to the inclined surface 501 is transmitted from the incident light 1000. It has a light path extending in a straight straight line in parallel. The lower prism part (Pa) and the upper prism part (Pb) are different materials, and in particular, when the refractive index of the upper prism part (Pb) is smaller than the lower prism part (Pa), the direction further away from the normal direction of the inclined surface 501 It proceeds to the second transmitted light 2002 refracted by. The upper layer 200 is in contact with the upper surface of the upper prism part Pb. When the upper layer 200 has the same refractive index as the lower layer 100, at the interface between the upper prism portion Pb and the upper layer 200, the upper layer 200 proceeds from the low refractive medium to the high refractive medium, and thus the third refracted closer in the normal direction. Proceed to transmitted light (2003). That is, in the process of passing through the upper layer 200 from the lower prism part Pa to the upper prism part Pb, the light path has a path that is further refracted in the normal direction of the surface of the light control film LCF.

Here, when the intermediate layer 300 is not divided into an upper prism portion Pb and a lower prism portion Pa, the transmitted light 2001 follows the path shown by the dotted arrow 2001', and thus the nano light absorbing layer ( 500) can be absorbed and destroyed. However, when the refractive index of the upper prism part Pb is lower than that of the lower prism part Pa, it may be refracted at the hypotenuse 501 to emit light from the light control film LCF. As a result, since the amount of light is increased in the front direction, the outgoing light efficiency can be improved.

The light that has passed through the upper layer part 200 is emitted from the light control film LCF as the emission light 3000. The upper layer 200 may be a layer disposed at the outermost side of the display panel including the light control film LCF. In this case, the upper surface of the upper layer 200 is in contact with air. When the refractive index of the upper layer 200 is greater than that of air, the emitted light 3000 is refracted in a direction further away from the normal of the surface of the upper layer 200. In this case, the refraction angle of the emission light 3000 is determined as the second viewing angle α.

Among the incident light 100, incident light having a wider angle than the diagonal extension direction of the nano light absorbing layer 500 is blocked and absorbed by the nano light absorbing layer 500. Accordingly, the direction of travel of light that is not blocked by the light control film LCF and transmitted determines the second viewing angle α.

In the case of the second embodiment, compared with the first embodiment, the value of the second viewing angle α may have a value smaller than the first viewing angle θ. In particular, in the second embodiment, since the hypotenuse 501 is inclined from upper right to lower left, it has a structure that can mainly affect light incident from the left region R. Accordingly, the viewing angle may have an asymmetric viewing angle range based on the normal direction of the light control film (LCF).

For example, as shown in FIG. 5B, the right viewing angle may have a smaller value than the left viewing angle. That is, the left viewing angle may have the first viewing angle θ, while the right viewing angle may have the second viewing angle α. This structure can be applied to devices that need to provide a narrower viewing angle in the right direction.

As another example, although not described with reference to the drawings, the refractive index of the upper prism portion Pb may have a value greater than that of the lower prism portion Pa. In this case, contrary to the case of FIG. 5A, it may be refracted in a direction closer to the normal of the hypotenuse 501. As a result, the second viewing angle α may have a larger angle than the first viewing angle θ.

In this case, as compared with the first embodiment, the value of the second viewing angle α may have a larger value than the first viewing angle θ. That is, the left viewing angle may have a first viewing angle θ, while the right viewing angle may have a second viewing angle α greater than the first viewing angle θ. This structure can be applied to a display device that needs to provide a wider viewing angle in the right direction.

<Third Example>

In the light control film (LCF) according to the first and second embodiments of this application described so far, a case where incident light is emitted in the normal direction of the surface of the light control film (LCF) has been described. As a third example of this application, the light control film LFC may be configured to emit light in a direction inclined at a predetermined angle to one side with respect to the normal of the surface of the light control film LFC. Hereinafter, a third embodiment of this application will be described with reference to FIG. 6. 6 is a cross-sectional view showing the structure of a light control film according to a third embodiment of this application.

Referring to FIG. 6, the light control film (LCF) according to the third embodiment of this application has the same basic configuration as the second embodiment shown in FIG. 5A. There is a difference in that the light absorbing layer 500 is inclined at a certain angle with respect to a vertical line. For example, the light absorbing layer 500 may be disposed to be inclined by δ° to the right based on a vertical line direction. In this case, the light emitted from the light control film LCF is emitted in a direction inclined by δ° to the right with respect to the normal line of the light control film LCF.

According to the third exemplary embodiment of the present application, the light control film LCF may provide light emitted in a direction inclined in a specific direction without tilting the light control film LCF in a specific direction. In addition, based on the principle as described in FIG. 3A, the light absorbing layer 500 according to the third embodiment of this application may provide only a specific range of viewing range. As shown in Figure 6, the light control film (LCF) according to the third embodiment of this application, with respect to the normal direction of the light control film (LCF), providing the exit light in a direction inclined by δ° to one side, , The viewing range can be controlled to provide only an area within the ±θ° range based on δ°.

<Fourth embodiment>

Hereinafter, a fourth embodiment of this application will be described with reference to FIG. 7. 7 is a cross-sectional view showing the structure of a light control film according to a fourth embodiment of this application.

Referring to FIG. 7, the light control film (LCF) according to the fourth embodiment of this application has the same basic configuration as the third embodiment shown in FIG. 6. If there is a difference, it is characterized in that the refractive index of the nano light absorbing layer 500 is smaller than that of the intermediate layer 300. For example, the refractive index of the nano light absorbing layer 500 is characterized in that it is less than the refractive index of the intermediate layer 300 by about 0.05 to 0.15. For example, when the refractive index of the intermediate layer 300 is 1.60, the refractive index of the nano light absorbing layer 500 may be 1.50. As another example, when the refractive index of the intermediate layer 300 is 1.53, the refractive index of the nano light absorbing layer 500 may be 1.45. Also, the intermediate layer 300 may have the same refractive index as the lower layer 100 and the upper layer 200.

As described above, since the refractive index of the nano light absorbing layer 500 is lower than that of the intermediate layer 300, light passing through the lower layer 100 and the intermediate layer 300 is not reflected by the nano light absorbing layer 500, and the nano light absorbing layer ( 500) can be refracted or absorbed. That is, in the case of light incident from the high refractive medium to the low refractive medium, the critical angle of total reflection becomes larger, so that the reflectance decreases and the refractive index increases. As a result, when the refractive index of the nano light absorbing layer 500 is lower than the refractive index of the intermediate layer 300, a large amount of light among the lights that may have been reflected by the nano light absorbing layer 500 will be absorbed by the nano light absorbing layer 500. I can.

For example, as shown in FIG. 7, light traveling from the right area to the nano light absorbing layer 500 disposed on the left may not be reflected, but may be absorbed by the nano light absorbing layer 500. As a result, the viewing angle in the right direction may have a β smaller than θ.

On the other hand, as shown in FIG. 7, light traveling from the left area to the nano light absorbing layer 500 disposed on the right may be reflected by total reflection and emitted to the left. The reason is that, since the nano light absorbing layer 500 is inclined to the right, even if the refractive index of the nano light absorbing layer 500 has a lower value than the intermediate layer 300, the nano light absorbing layer 500 from the left region R This is because the incident angle of incident light is likely to be greater than the overall critical angle. As a result, the viewing angle in the left direction may have a viewing angle substantially equal to θ.

In conclusion, since the basic configuration of the fourth embodiment is the same as that of the third embodiment, the light control film (LCF) according to the fourth embodiment is a nano light absorbing layer 500 inclined at a certain angle with respect to a vertical line, which is a normal direction of the surface. ). For example, the nano light absorbing layer 500 may be disposed at an inclined δ° to the right based on a vertical line direction. In this case, the light emitted from the light control film LCF is emitted in a direction inclined by δ° to the right with respect to the normal line of the light control film LCF.

According to the fourth exemplary embodiment of the present application, the light control film LCF may provide light emitted in a direction inclined in a specific direction without tilting the light control film LCF in a specific direction. In addition, based on the principle as described in FIG. 3A, the light absorbing layer 500 according to the third embodiment of this application may provide only a specific range of viewing range. In particular, as shown in FIG. 7, the light control film (LCF) according to the fourth embodiment of this application transmits outgoing light in a direction inclined δ° to the right with respect to the normal direction of the light control film (LCF). However, the viewing range can be controlled to be provided only in a region within a range of θ° to the left and β° (<θ°) to the right based on δ°.

<Fifth embodiment>

Hereinafter, a fifth embodiment of this application will be described with reference to FIG. 8. 8 is a cross-sectional view showing the structure of a light control film according to a fifth embodiment of this application.

The light control film LCF shown in FIG. 8 has substantially the same structure as the light control film LCF shown in FIG. 7. If there is a difference, the intermediate layer 300 has a lower prism portion (Pa) disposed below the hypotenuse 501 (or inclined surface) connecting the diagonal points of the adjacent nano light absorbing layers 500 between the nano light absorbing layers 500. ) And the upper prism part (Pb) disposed on the upper part. Here, the lower prism portion Pa and the upper prism portion Pb may be the same as those described in the second embodiment.

The upper prism part Pb may have a lower refractive index than the lower layer 100 and the upper layer 200. As an example, the refractive index of the upper prism part Pb may have a value lower than the refractive index of the lower prism part Pa by 0.05 to 0.1. At the same time, it is characterized in that the refractive index of the nano light absorbing layer 500 is smaller than that of the intermediate layer 300. For example, the refractive index of the nano light absorbing layer 500 is characterized in that it is less than the refractive index of the intermediate layer 300 by about 0.05 to 0.15.

In summary, as shown in FIG. 8, the refractive index n ₁₀₀ of the lower layer 100, the refractive index n ₂₀₀ of the upper layer ₂₀₀ , and the refractive index n _Pa of the lower prism part Pa have the same refractive index. I can. In addition, the refractive index n _Pb of the upper prism portion Pb may be lower than the refractive index n _Pa of the lower prism portion Pa. At the same time, the refractive index n ₅₀₀ of the nano light absorbing layer 500 may be lower than the refractive index n _Pb of the upper prism portion Pb. In this case, the refractive index n ₅₀₀ of the nano light absorbing layer 500 is naturally lower than that of the lower prism portion Pa.

For example, the lower prism part Pa may have a refractive index of 1.53, and the upper prism part Pb may have a refractive index of 1.48. In this case, the refractive index of the nano light absorbing layer 500 may be 1.41. When a metal material is used for the nano light absorbing layer 500, it may be very difficult to select a material having a refractive index of less than 1.5. On the other hand, it is easy to select a material having a relatively high refractive index for the intermediate layer 300 made of a transparent organic material. Considering this situation, the refractive index of the nano light absorbing layer 500 may be 1.50, the lower prism part Pa may have a refractive index of 1.62, and the upper prism part Pb may have a refractive index of 1.55.

In such a structure, as described in the second embodiment, the incident light inclined to the right passes through the lower layer 100, the intermediate layer 300, and the upper layer 200, and is refracted to be close to the normal direction of the surface of the light control film (LCF). do. Thereafter, the light is emitted to the outside of the light control film LCF, and is emitted as an emission light 3000 having an emission angle (δ+γ)° with respect to the normal line.

The viewing angle ranges set by the light control film according to the third to fifth embodiments of this application will be compared and described with reference to FIG. 9. 9 is a cross-sectional view comparing viewing angle ranges set by the light control film according to the third to fifth embodiments of this application. Referring to FIG. 9, the left viewing angle is based on a front direction in which the nano light absorbing layer 500 is inclined δ° to the right, and left viewing angles according to the third to fifth embodiments may all have the same θ°. On the other hand, based on the front direction inclined δ° to the right, the right viewing angle is θ° in the third embodiment, β° smaller than θ° in the fourth embodiment, and smaller than β° in the fifth embodiment. can have γ°.

Hereinafter, a display device including a light control film (LCF) according to exemplary embodiments of the present application will be described with reference to FIGS. 10A to 10E. 10A to 10E are cross-sectional views illustrating a structure of an electroluminescent display device including a light control film according to each of the first to fifth embodiments of this application.

Referring to FIG. 10A, the display device according to the first embodiment of this application includes a display panel DP and a light control film LCF disposed on a front surface of the display panel DP. The display panel DP includes a substrate SUB, a display layer EL formed on the substrate SUB, an encapsulation layer ENC covering the display layer EL, an optical layer POL disposed on the encapsulation layer ENC, and A cover substrate CB disposed on the optical layer POL may be provided. In some cases, the optical layer POL and the cover substrate CB may be integrally formed.

The substrate SUB is preferably formed of a transparent material. In the display layer EL, pixel areas arranged in a matrix manner are defined. A driving element and a light emitting element may be disposed in each pixel area. The driving element may include a thin film transistor and an auxiliary capacitor. The light-emitting device may be an electroluminescent device in which the degree of brightness is adjusted by a driving device. The electroluminescent device may include an organic light emitting diode or an inorganic light emitting diode.

The encapsulation layer ENC is to protect the display layer EL and prevents air or foreign substances from penetrating from the outside. The encapsulation layer ENC may have a structure in which an inorganic material layer and an organic material layer are alternately stacked in multiple layers.

The optical layer POL is for improving display characteristics of a display device, and may be a polarizing film for preventing a problem of deteriorating display performance due to reflection of light coming from the outside. For example, a quarter-wavelength film may be provided.

The cover substrate CB may be a transparent and highly rigid substrate such as thick glass. The cover substrate CB may be a transparent protective substrate for preventing damage to the optical layer POL, the encapsulation layer ENC, and the display layer EL disposed below by an external force.

The light control film LCF according to this application is attached to the outer surface of the cover substrate CB. Particularly, when it is necessary to narrow the viewing angle in the vertical direction when viewed from the front of the display device, it is preferable to arrange the length L of the nano light absorbing layer 500 to advance in the left-right direction of the display device. In addition, when it is necessary to narrow the viewing angle in the left and right direction, it is preferable to arrange the nano light absorbing layer 500 so that the length L of the display device proceeds in the vertical direction.

The light control film (LCF) according to this application has a structure in which thin thin films of 1.0 μm or less, that is, nanometer units, are arranged at intervals of 20 μm or less, and thus may function as a linear polarization. Specifically, among the light incident on the light control film (LCF), all polarization components in the length direction of the nano light absorption layer 500 are absorbed, and only polarization components in the width direction of the nano light absorption layer 500 are transmitted.

In addition, the light linearly polarized by the light control film (LCF) in the arrangement direction (or width direction) of the nano light absorption layer 500 is caused by a quaternary wave plate, which is an optical layer POL disposed under the cover substrate CB. It is converted into circularly polarized light, and when the circularly polarized light is reflected from the display layer, it becomes circularly polarized light whose phase is reversed. The phase is reversed, but the circularly polarized light is again changed to linearly polarized light by the quaternary wave plate, and the direction of the linearly polarized light at this time becomes a direction coinciding with the longitudinal direction of the nano light absorbing layer 500 of the light control film (LCF). All of them are absorbed by the absorption layer 500. As a result, even if external light is reflected from the display layer, it is not emitted to the outside of the display device and is not recognized by the user.

In the display device including the light control film (LCF) according to the first embodiment, a narrow viewing angle in which the normal direction and the front direction of the display device surface coincide, and the viewing angle range is θ° from the front direction to the left and right (or up and down) It can have a range.

As such, the light control film (LCF) according to this application not only can adjust the viewing angle, but also has a linear polarization function. Therefore, a separate linear polarizing plate is not required to remove external reflected light. As a result, the overall thickness of the display device can be secured to be thinner.

Referring to FIG. 10B, the display device according to the second embodiment of this application includes a display panel DP and a light control film LCF disposed on a front surface of the display panel DP. Since the display panel DP is the same as that of FIG. 10A, detailed descriptions are omitted. The light control film LCF has a structure in which the intermediate layer 300 is divided into a lower prism part Pa and an upper prism part Pb. In particular, the upper prism portion Pb has a lower refractive index than the lower prism portion Pa. In this case, the left viewing angle is θ°, but the right viewing angle may be α° smaller than θ°. That is, an asymmetric narrow viewing angle can be implemented.

Referring to FIG. 10C, the display device according to the third embodiment of this application includes a display panel DP and a light control film LCF disposed on a front surface of the display panel DP. Since the display panel DP is the same as that of FIG. 10A, detailed descriptions are omitted. The light control film LCF has a structure in which the nano light absorbing layer 500 is inclined by δ° in the right direction with respect to the normal of the surface of the light control film LCF. In the display device including the light control film LCF according to the third embodiment, a direction inclined δ° to the right from the normal direction of the surface of the display device is set as the front direction. In addition, it may have a narrow viewing angle range in which the viewing angle range is θ° from the front to the left and right (or vertically).

Referring to FIG. 10D, the display device according to the fourth exemplary embodiment of the present application includes a display panel DP and a light control film LCF disposed on a front surface of the display panel DP. Since the display panel DP is the same as that of FIG. 10A, detailed descriptions are omitted. On the other hand, the light control film (LCF) has a structure in which the nano light absorbing layer 500 is inclined by δ° in the right direction based on the normal of the surface of the light control film (LCF). As a result, a direction inclined δ° to the right from the normal direction of the surface of the display device is set as the front direction.

In addition, the nano light absorbing layer 500 has a lower refractive index than the intermediate layer 300. Therefore, the light that can be reflected from the nano light absorbing layer 500 is also refracted by the nano light absorbing layer 500 to minimize the reflectance, so that the narrow viewing angle range of each θ° from the front direction to the left and right (or up and down) Not only can it eliminate the leakage light that escapes, but it can also make the viewing angle narrower. In particular, it is possible to selectively narrow the viewing angle of the side at which the light control film LCF is inclined.

In conclusion, in the display device including the light control film (LCF) according to the fourth embodiment, the left viewing angle is θ°, but the right viewing angle is δ° to the right from the normal direction of the display device surface. It may be a β° smaller than θ°. That is, an asymmetric narrow viewing angle can be implemented.

Referring to FIG. 10E, the display device according to the fifth exemplary embodiment of the present application includes a display panel DP and a light control film LCF disposed on a front surface of the display panel DP. Since the display panel DP is the same as that of FIG. 10A, detailed descriptions are omitted. On the other hand, the light control film (LCF) has a structure in which the nano light absorbing layer 500 is inclined by δ° in the right direction based on the normal of the surface of the light control film (LCF). As a result, a direction inclined δ° to the right from the normal direction of the surface of the display device is set as the front direction.

In addition, the nano light absorbing layer 500 has a lower refractive index than the intermediate layer 300. Therefore, the light that can be reflected from the nano light absorbing layer 500 is also refracted by the nano light absorbing layer 500 to minimize the reflectance, so that the narrow viewing angle range of each θ° from the front direction to the left and right (or up and down) Not only can it eliminate the leakage light that escapes, but it can also make the viewing angle narrower. In particular, it is possible to selectively narrow the viewing angle of the side at which the light control film LCF is inclined.

In addition, the light control film LCF has a structure in which the intermediate layer 300 is divided into a lower prism portion Pa and an upper prism portion Pb. In particular, the upper prism portion Pb has a lower refractive index than the lower prism portion Pa. In this case, the left viewing angle is Θ, but the right viewing angle may be γ° smaller than θ°. In particular, γ° has a narrower viewing angle smaller than β°. That is, an asymmetric narrow viewing angle can be implemented.

In the embodiments and drawings of this application described so far, only the case where the light control film (LCF) is bonded to the upper surface of the cover substrate (CB) has been described. However, depending on the need for product configuration, it may be adhered to the inner surface of the cover substrate CB. For example, the light control film LCF may be disposed between the cover substrate CB and the optical layer POL. As another example, the cover substrate CB may be deleted. In this case, the optical layer POL, the encapsulation layer ENC, and the display layer EL may be sequentially stacked and disposed under the light control film LCF.

Features, structures, effects, and the like described in the above-described examples of the present application are included in at least one example of the present application, and are not necessarily limited to one example. Further, the features, structures, effects, etc. exemplified in at least one example of the present application may be combined or modified for other examples by a person having ordinary knowledge in the field to which this application belongs. Accordingly, contents related to such combinations and modifications should be construed as being included in the scope of the present application.

The present application described above is not limited to the above-described embodiment and the accompanying drawings, and that various substitutions, modifications, and changes are possible within the scope of the technical matters of the present application. It will be obvious to those who have the knowledge of. Therefore, the scope of the present application is indicated by the claims to be described later, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application.

LCF: light control film 100: lower layer
200: upper layer 300: middle layer
500: nano light absorbing layer a: length of the lower layer
b: width of the lower layer t1: thickness of the lower layer (first)
t2: thickness of the upper layer (second) T: thickness of the intermediate layer
W: width of the nano light absorbing layer L: length of the nano light absorbing layer
H: height of the nano light absorbing layer G: arrangement interval of the nano light absorbing layer

Claims (20)

A lower layer disposed on a plane consisting of a first axis and a second axis;
An upper layer having the same shape as and facing the lower layer;
An intermediate layer having a predetermined thickness and interposed between the lower layer and the upper layer;
A plurality of nano-light absorbing layers having a predetermined width on the first axis, a predetermined length on the second axis, and a height corresponding to the thickness of the intermediate layer, and disposed at regular intervals along the first axis in the intermediate layer,
The ratio of the arrangement interval to the width of the nano light absorbing layer is a light control film having any one value selected from 10:1 to 20:1. The method of claim 1,
The width of the nano light absorbing layer is a light control film having any one value selected from 0.1㎛ to 1.0㎛. The method of claim 1,
The ratio of the arrangement interval to the height of the nano light absorbing layer is a light control film having any one value selected from 1:1 to 1:4. The method of claim 1,
The lower layer, the intermediate layer, and the upper layer are light control films having a higher refractive index than air. The method of claim 1,
One of the nano light absorbing layers,
A light control film in which at least two or more thin film layers are laminated. The method of claim 5,
A light control film having a width of one thin film layer included in the nano light absorbing layer having a value selected from 0.01 μm to 0.1 μm. The method of claim 5,
One of the nano light absorbing layers,
A first thin film layer having a first reflectance;
A light control film in which second thin film layers having a second reflectance different from the first reflectance are stacked on each other. The method of claim 7,
One of the nano light absorbing layers,
A light control film in which a third thin film layer having a third reflectance different from the first reflectance and the second reflectance is further stacked. The method of claim 1,
One of the nano light absorbing layers,
A first thin film layer having a first transmittance;
A light control film in which a second thin film layer having a second transmittance different from the first transmittance is stacked on each other. The method of claim 9,
One of the nano light absorbing layers,
A light control film in which a third thin film layer having a third transmittance different from the first transmittance and the second transmittance is further stacked. The method of claim 1,
The plurality of nano light absorbing layers include a first nano light absorbing layer and a second nano light absorbing layer adjacent to each other at the arrangement interval,
The intermediate layer is a light control film including a lower prism portion disposed below and an upper prism portion disposed above the inclined surface connecting the lower end of the second nano light absorbing layer from the upper end of the first nano light absorbing layer. The method of claim 11,
The lower prism part has a first refractive index,
The upper prism portion is a light control film having a second refractive index smaller than the first refractive index. The method of claim 1,
The upper layer, the lower layer, and the intermediate layer include a transparent organic material,
The nano light absorbing layer is a light control film comprising a material that absorbs visible light. The method of claim 13,
The nano light absorption layer,
Silicon nitride (SiN), titanium nitride (TiN), silicon carbide (SiC), tantalum (Ta), titanium (Ti), tungsten (W), copper oxide (CuO), aluminum oxide (Al ₂ O ₃ ), iron oxide (Fe ₃ O ₄ ), a carbon allotrope, and a light control film comprising any one selected from tantalum oxide (Ta ₂ O ₅ ). The method of claim 1,
The nano light absorption layer,
The light control film inclined at an angle in one direction based on the normal line of the light control film surface. The method of claim 15,
The nano light absorption layer,
A light control film having a refractive index smaller than that of the upper layer, the lower layer, and the intermediate layer. The method of claim 15,
The plurality of nano light absorbing layers include a first nano light absorbing layer and a second nano light absorbing layer adjacent to each other at the arrangement interval,
The intermediate layer is a light control film including a lower prism portion disposed below and an upper prism portion disposed above the inclined surface connecting the lower end of the second nano light absorbing layer from the upper end of the first nano light absorbing layer. The method of claim 17,
The upper layer, the lower layer, and the lower prism part have the same refractive index,
The upper prism part has a lower refractive index than the lower prism part,
The nano light absorption layer is a light control film having a lower refractive index than the upper prism portion and the lower prism portion. The method of claim 18,
The one side direction in which the nano light absorbing layer is inclined is,
A light control film in which the upper end of the nano light absorbing layer is inclined in a direction toward the upper prism part. A substrate on which a plurality of pixel regions are defined;
A display layer including a driving element and a light emitting element disposed on the substrate to correspond to the pixel region;
An encapsulation layer covering the display layer;
A quarter wave plate disposed on the encapsulation layer;
A cover substrate disposed on the quarter wave plate; And
A display device comprising the light control film according to any one of claims 1 to 19 disposed on the cover substrate.

Images