KR102284255B1 - Optical film for mini led or micro led backlight unit - Google Patents

Abstract

An optical film that transmits light emitted from a mini LED (light emitting diode) or micro LED is disclosed. The optical film may include a first base film and a diffusion lens layer disposed on one side of the first base film and including a plurality of quadrangular pyramid-shaped lenses. Here, the apex angle, which is an angle between two opposing surfaces of the four surfaces disposed on the quadrangular pyramid-shaped lens, may be set based on a separation angle formed by refracting light passing through the lens.

Description

Optical film for mini LED or micro LED backlight unit {OPTICAL FILM FOR MINI LED OR MICRO LED BACKLIGHT UNIT}

The present invention relates to an optical film for a mini LED or micro LED backlight unit, and more particularly, to an optical film for separating and diffusing transmitted mini LED light or micro LED light.

As the light-energy conversion efficiency of LEDs increases with the progress of research on LEDs (light emitting diodes, light emitting diodes), LEDs are rapidly replacing existing light emitting devices.

LEDs currently being developed have advantages such as miniaturization, light weight, and low power consumption. Accordingly, LEDs are being actively used as light sources for various image display devices.

The size of the LED chip is gradually getting smaller. Examples of miniature LED chips are mini LEDs and micro LEDs. In general, the chip size of the mini LED may be defined as 100 μm to 200 μm, and the chip size of the micro LED may be defined as 5 μm to 100 μm. In the case of mini LED or micro LED, each LED chip individually becomes a pixel or a light source, so restrictions on the size and shape of the display are eliminated, and sharper image quality can be realized than when a conventional light source is used.

Along with the miniaturization of LED chip size, research on optical films to supplement LED light characteristics is also active.

The present invention provides an optical film that minimizes the loss of luminance of light emitted from a mini LED or micro LED and limits the occurrence of hot spots by uniformly spreading the light.

The present invention provides an optical film that minimizes loss of luminance of light while converting light emitted from a mini LED or micro LED into white light and uniformly diffuses light.

An optical film transmitting light emitted from a mini LED (light emitting diode) or micro LED according to various embodiments of the present disclosure is disposed on a first base film and one side of the first base film, and has a plurality of quadrangular pyramid shapes. It may include a diffusion lens layer including a lens. Here, the apex angle, which is an angle between two opposing surfaces of the four surfaces disposed on the quadrangular pyramid-shaped lens, may be set based on a separation angle formed by refracting light passing through the lens.

According to various embodiments of the present disclosure, it is possible to minimize the loss of luminance of light emitted from the mini LED or micro LED, and to limit the occurrence of hot spots by uniformly spreading the light.

According to various embodiments of the present disclosure, it is possible to minimize loss of luminance of light while converting light emitted from the mini LED or micro LED into white light, and uniformly spread the light.

1 is an exploded view of a liquid crystal display according to an embodiment of the present invention.
2 shows a direct-type LED light source according to an embodiment of the present invention.
3 is a cross-sectional view of an optical film according to an embodiment of the present invention.
4 illustrates optical separation according to an embodiment of the present invention.
5 illustrates optical separation according to another embodiment of the present invention.
Figure 6a shows one side of the optical film according to another embodiment of the present invention.
6B is a perspective view of an optical film according to another embodiment of the present invention.
7 shows a side of an optical film according to another embodiment of the present invention.
8 shows a measurement result of light separation according to an embodiment of the present invention.
9 illustrates a change in a light separation angle of a diffusion lens layer according to an embodiment of the present invention.
10 is a cross-sectional view of an optical film according to another embodiment of the present invention.
11 shows the International Lighting Commission color space according to an embodiment of the present invention.
12 shows a spectral spectrum measurement result according to an embodiment of the present invention.
13 is a cross-sectional view of an optical film according to another embodiment of the present invention.
14 is a cross-sectional view of an optical film according to another embodiment of the present invention.
15 is a cross-sectional view of an optical film according to another embodiment of the present invention.
16 is a cross-sectional view of an optical film according to another embodiment of the present invention.
17 shows a performance test result of an optical film according to an embodiment of the present invention.
18 shows a performance test result of an optical film according to another embodiment of the present invention.

Hereinafter, the principle of operation of a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, when it is determined that a detailed description of a related well-known function or configuration may obscure the gist of the present disclosure in describing an embodiment of the present invention, the detailed description thereof will be omitted. And the terms used below are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of the user or operator. Therefore, the definitions of the terms used should be interpreted based on the contents and corresponding functions throughout this specification.

A backlight unit is a light source of a liquid crystal display (LCD). A liquid crystal display device is an element that does not emit light by itself. Accordingly, the backlight unit including the light source irradiates light toward the liquid crystal panel from the rear surface of the liquid crystal display device. Through this, an identifiable image can be implemented.

The backlight unit uses a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED, hereinafter referred to as LED) as light sources.

The backlight unit is divided into an edge type and a direct type according to the arrangement structure of the light source. The direct type can be divided and driven compared to the edge type, so that it is possible to implement an image more delicately than the edge type.

Hereinafter, an optical film included in the direct type LED backlight unit will be described in detail.

1 is an exploded view of a liquid crystal display according to an embodiment of the present invention.

Referring to FIG. 1 , a liquid crystal display (or liquid crystal display (LCD) device) 1 includes a backlight unit 10 and a liquid crystal panel 20 . In general, the backlight unit 10 may be provided at the rear of the liquid crystal panel 20 to irradiate light to the liquid crystal panel 20 . The backlight unit 10 includes a light source 11 , a reflective sheet 12 , a color conversion sheet 13 , a diffusion lens sheet 14 , a diffusion sheet 15 , 18 , a prism sheet 16 , 17 , and a reflective polarizing sheet (19) may be included. Here, the backlight unit 10 may be formed in which at least one of the components 11 to 19 included in the backlight unit 10 is not included or other components other than the components 11 to 19 are added. In addition, the backlight unit 10 may be formed in various combinations including at least one of the components 11 to 19 included in the backlight unit 10 .

The light source 11 provides light. For example, the light source 11 may include a plurality of LED chips that emit light. For example, referring to FIG. 2 , the LED chips 11 ′-1 may be arranged in a tiled pattern to form a direct type 11 ′.

Depending on the size of the LED chip, large LED (chip size: 1,000 μm or more), middle LED (chip size: 300 - 500 μm), small LED (chip size: 200 - 300 µm), mini LED (chip size 100 - 200 µm), and micro LED (chip size: 100 µm or less). Here, the LED may include a material such as InGaN or GaN.

As the chip size of the LED of the backlight unit decreases, the number of LEDs can be easily adjusted, so that the luminance characteristic and color uniformity of the liquid crystal display 1 can be improved and slim. In addition, as the chip size of the LED becomes smaller, power consumption can be reduced, thereby reducing battery consumption of the portable device and extending the battery life.

When using a mini LED or micro LED compared to the existing direct type LED, the size of the LED becomes smaller, so local dimming is possible. Local dimming can improve picture quality and save power. Here, the local dimming is a technology for controlling the brightness of an LED used as a backlight based on a configuration or characteristic of a screen, and is a technology capable of remarkably improving a contrast ratio and reducing power consumption. As an example of local dimming, dark colors are expressed by adjusting the brightness of the mini LED or micro LED corresponding to the dark screen to be relatively dark, and the brightness of the mini LED or micro LED corresponding to the bright screen is relatively brightened to display vivid colors. can express

The reflective sheet 12 reflects light. The reflective sheet 12 transmits light in the divergence direction of the light emitted from the light source 11 , and reflects the light reflected by the interface reflection from the upper portion in the divergence direction. Through this, the loss of light can be minimized. The reflective sheet 12 may perform light recycling.

The color conversion sheet 13 converts the color of the light emitted from the light source 11 . For example, the light of the mini LED or micro LED is blue light (450 nm). In this case, the blue light needs to be converted into white light. The color conversion sheet 13 may convert blue light into white light while transmitting blue light.

The diffusion lens sheet 14 diffuses light. The diffusion lens sheet 14 arranges a plurality of light diffusion lenses on one surface. For example, the light diffusion lens may be formed in a pyramid shape to promote light diffusion.

The diffusion sheets 15 and 18 may uniformly disperse the incident light. The diffusion sheets 15 and 18 include at least one or more of a curable resin (eg, urethane acrylate, epoxy acrylate, ester acrylate, ester acrylate, and radical generating monomer) to which light diffusing agent beads are added. It can be used alone or mixed) to cause light diffusion by the optical powder bead by applying the solution. In addition, in the diffusion sheets 15 and 18, a protrusion pattern (or protrusion) having a uniform or non-uniform size shape (eg, a spherical shape) may be disposed to promote light diffusion.

The prism sheets 16 and 17 may condense incident light using an optical pattern formed on the surface and emit the light to the liquid crystal panel 20 . The prism sheets 16 and 17 may be formed of an optical pattern layer in which an optical pattern in the form of a triangular array having a generally inclined surface of 45° is formed on an upper portion of the translucent base film to improve luminance in the front direction.

The reflective polarizing sheet 19 is provided on the prism sheets 16 and 17 to transmit one polarized light with respect to the light collected from the prism sheets 16 and 17 and reflect the other polarized light downward to recycle the light. .

The liquid crystal panel 20 modulates the light irradiated from the light source 11 in a predetermined pattern according to an electrical signal. The modulated light passes through the color filter and the polarization filter disposed on the front of the liquid crystal panel 20 to configure the screen.

The configuration of the liquid crystal display 1 according to an embodiment of the present invention has been described above. Hereinafter, various embodiments of the present application will assume a case of using a mini LED or micro LED as the light source 11 of the backlight unit, but include a light source 11 in which LEDs of uniform or various sizes are directly disposed. Various embodiments of the present disclosure may be applied without limitation to the backlight unit.

Hereinafter, an optical film according to various embodiments of the present invention will be described in detail.

Hereinafter, the optical film is defined as the diffusion lens sheet 14 of FIG. 1 , or the diffusion lens sheet 14 and the reflection sheet 12 of FIG. 1 , the color conversion sheet 13 , the diffusion lens sheet 14 , and the diffusion lens sheet 14 of FIG. 1 . It may be defined as a combination of at least one of the sheets 15 and 18 , the prism sheets 16 and 17 , and the reflective polarizing sheet 19 .

3 is a cross-sectional view of an optical film according to an embodiment of the present invention.

Referring to FIG. 3 , the optical film 30 may include a first base film 31 and a diffusion lens layer 32 . The optical film 30 may transmit light emitted from a mini LED (light emitting diode) or a micro LED.

The first base film 31 may support the diffusion lens layer 32 . The first base film 31 may be made of, for example, PET, PC, PP, or the like.

The diffusion lens layer 32 may be disposed on one side of the first base film 31 . In addition, the diffusion lens layer 32 may include a plurality of quadrangular pyramid-shaped lenses 32-1 to 32-5. In this case, the lenses 32-1 to 32-5 of the quadrangular pyramid shape may be regularly arranged. Here, the plurality of quadrangular pyramid-shaped lenses 32-1 to 32-5 may have the same size and shape, or different sizes but may have similar shapes. Also, the diffusion lens layer 32 may be defined as including the first base film 31 .

)(32-1-1)은 사각뿔 형상의 렌즈(32-1)에 배치되는 네 개의 면 중 두 개의 마주보는 면 사이의 각도로 정의될 수 있다. 예를 들어, 정점각은 40° 내지 150° 내에서 정의되고, 높이(32-1-2)는 약 10μm, 폭(32-1-3)은 약 20μm로 정의될 수 있다. 이 경우, 정점각(32-1-1)은 사각뿔 형상의 렌즈(32-1)를 투과하는 광이 굴절되어 형성하는 분리각에 기초하여 설정될 수 있다.For example, the vertex angle (

) (32-1-1) may be defined as an angle between two opposing surfaces among four surfaces disposed on the quadrangular pyramid-shaped lens 32-1. For example, the apex angle may be defined within 40° to 150°, the height 32-1-2 may be defined as about 10 μm, and the width 32-1-3 may be defined as about 20 μm. In this case, the apex angle 32-1-1 may be set based on a separation angle formed by refracting light passing through the quadrangular pyramid-shaped lens 32-1.

)은 미니 LED 또는 마이크로 LED에서 방사되는 광이 제1 베이스 필름(31')의 일 측 방향(33)으로 입사하여 사각뿔 형상의 렌즈(32'-1)를 투과하는 경우에 형성될 수 있다. 여기서, 사각뿔 형상의 렌즈(32'-1)를 투과하는 광의 입사각은 제1 베이스 필름(31')의 일 면과 직각을 형성한다.4, the separation angle of light (

) may be formed when light emitted from the mini-LED or micro-LED is incident in one side direction 33 of the first base film 31' and passes through the lens 32'-1 having a quadrangular pyramid shape. Here, the incident angle of the light passing through the quadrangular pyramid-shaped lens 32'-1 forms a right angle with one surface of the first base film 31'.

)은 미니 LED 또는 마이크로 LED에서 방사되는 광이 제1 베이스 필름(31'')의 타 측 방향(33')으로 입사하여 사각뿔 형상의 렌즈(32''-1)를 투과하는 경우에 형성될 수 있다. 여기서, 사각뿔 형상의 렌즈(32''-1)를 투과하는 광의 입사각은 제1 베이스 필름(31'')의 일 면과 직각을 형성한다.Referring to Figure 5, the reverse (reverse) of the light-separation angle (

) is to be formed when the light emitted from the mini LED or micro LED is incident in the other direction 33' of the first base film 31'' and passes through the lens 32''-1 of the quadrangular pyramid shape. can Here, the incident angle of the light passing through the quadrangular pyramid-shaped lens 32''-1 forms a right angle with one surface of the first base film 31''.

로, 리버스-분리각은

로 정의될 수 있다.In the above example, the separation angle of light and the reverse-separation angle may be variously defined. For example, the separation angle of light is 1/

, the reverse-separation angle is

can be defined as

에 기초한 비율에 따라 정의될 수 있다. 예를 들어, 정점각

가 90인 경우, 사각뿔 형상의 렌즈(32-1)의 밑면의 높이(32-1-3)와 사각뿔 형상의 렌즈(32-1)의 높이(32-1-2)의 비율은 2:1로 정의될 수 있다.On the other hand, the height 32-1-3 of the bottom of the lens 32-1 of the quadrangular pyramid shape and the height 32-1-2 of the lens 32-1 of the quadrangular pyramid shape are the apex angles.

It can be defined according to a ratio based on For example, the vertex angle

is 90, the ratio of the height (32-1-3) of the bottom of the quadrangular pyramid-shaped lens 32-1 to the height (32-1-2) of the quadrangular pyramid-shaped lens 32-1 is 2:1 can be defined as

Figure 6a shows one side of the optical film according to another embodiment of the present invention.

6A shows a state in which the optical film 60 is viewed vertically from one side of the optical film 60 . Referring to FIG. 6A , one 61 of a plurality of quadrangular pyramid-shaped lenses disposed on one side of the optical film 60 includes an apex 61-1 and four surfaces 61-1 to 61-4. do.

Referring to FIG. 6B , a plurality of lenses having a quadrangular pyramid shape disposed on one side of the optical film 60 are regularly disposed. Here, the quadrangular pyramid shape may be referred to as a pyramid shape.

7 shows a side of an optical film according to another embodiment of the present invention.

7 shows a state in which the optical film is viewed vertically from one side of the optical film 70 .

Referring to FIG. 7 , the optical film 70 includes a plurality of quadrangular pyramid-shaped lenses having different sizes.

For example, the height of at least one 72 of the plurality of quadrangular pyramid-shaped lenses may be smaller than the height of the other one 71 of the plurality of quadrangular pyramid-shaped lenses. Here, the apex angle of at least one of the plurality of quadrangular pyramid-shaped lenses 72 may be the same as the apex angle of the other 71 of the plurality of quadrangular pyramid-shaped lenses. As the apex angles are the same, at least one 72 of the plurality of quadrangular pyramid-shaped lenses and the other 71 of the plurality of quadrangular pyramid-shaped lenses may have a similar quadrangular pyramid shape.

이다. 여기서, n은 자연수로 정의될 수 있다.In the above-described example, the height of at least one 72 of the plurality of quadrangular pyramid-shaped lenses is equal to the height of the other one 71 of the plurality of quadrangular pyramid-shaped lenses.

am. Here, n may be defined as a natural number.

According to the embodiment of FIG. 7 described above, when the optical film 70 is attached to another film or layer included in the backlight unit, the height of the optical film 70 is relatively high with the quadrangular pyramid-shaped lens 72 and the height. An air gap may be formed between the lenses 72 having a relatively low quadrangular pyramid shape. As the air gap is created, diffusion of light passing through the optical film 70 may be promoted and a decrease in luminance may be minimized.

In various embodiments of the present invention described above, a case in which the four surfaces (or lenses) disposed on the quadrangular pyramid-shaped lenses of the optical films 60 and 70 are the same (congruent) has been described in detail. However, it is not limited thereto. For example, the size and angle of the faces facing the X direction or the faces facing the Y direction among the four surfaces disposed on the lens of the quadrangular pyramid shape of the optical film are the same as each other, and are disposed on the lens of the quadrangular pyramid shape of the optical film The sizes and angles of the connecting surfaces among the four surfaces may be different from each other. In this case, the angle between the faces facing in the X direction among the four faces disposed on the lens having a quadrangular pyramid shape of the optical film and the angle between the faces facing the Y direction among the four faces disposed on the lens having the quadrangular pyramid shape of the optical film They may also be different from each other.

8 shows a measurement result of light separation according to an embodiment of the present invention.

FIG. 8 shows the light separation measurement results for the case where the mini LED light or the micro LED light is incident in the direction of the first base film 31 from the diffusion lens layer 32 of the optical film 30 of FIG. 3 .

9 illustrates a change in a light separation angle of a diffusion lens layer according to an embodiment of the present invention.

The first graph 91 shows the change in the light separation angle according to the change of the apex angle PY when light is incident in the outer direction 91-2 of the quadrangular pyramid of the diffusion lens layer 91-1. do. Referring to the first graph 91, it can be seen that the light separation angle decreases as the vertex angle increases.

The second graph 92 shows the change in the light separation angle according to the change in the apex angle when light is incident in the inner direction 92-2 of the quadrangular pyramid of the diffusion lens layer 92-1. Referring to the second graph 92, light separation is not performed until the apex angle increases to 100°, the maximum light separation occurs at the apex angle 105°, and as the apex angle increases from 105°, the light separation angle It can be seen that this decreases.

Referring to the first graph 91 and the second graph 92, it can be seen that target light separation can be induced by adjusting the vertex angle in a predetermined region.

In the above-described example, since incident light is separated (or diffused) by the action of the diffusion lens layer 32, a hot spot caused by the incident light can be reduced.

10 is a cross-sectional view of an optical film according to another embodiment of the present invention.

Referring to FIG. 10 , the optical film 100 may include a first base film 101 , a second base film 102 , a diffusion lens layer 103 , and a color conversion layer 104 .

Hereinafter, a description of the configuration overlapping with the contents of the above-described optical film will be omitted.

The first base film 101 and the second base film 102 may be disposed in parallel to protect the color conversion layer 104 .

The color conversion layer 104 converts colors. The color conversion layer 104 may convert blue light emitted from the mini LED or micro LED into white light.

The color conversion layer 104 may be disposed between the first base film 101 and the second base film 102 .

-sialon 형광체가 있다. 또한, 무기입자는 광의 균일한 산란을 유도하기 위한 것이다. 무기입자의 예로는 직경이 수백 나노미터인 TiO2, SiO2가 있다.The color conversion layer 104 may include a red phosphor, a green phosphor, and inorganic particles. Here, the red phosphor or green phosphor is a material that absorbs light emitted from the mini LED or micro LED to form red light or green light. For example, a red phosphor is a KSF (K ₂ SiF ₆ :Mn4+) phosphor, and a green phosphor is

-sialon phosphor is present. In addition, the inorganic particles are for inducing uniform scattering of light. Examples of inorganic particles include TiO2 and SiO2 with a diameter of several hundred nanometers.

For example, the color conversion layer 104 may be formed by stirring a red phosphor, a green phosphor, and inorganic particles in a resin (silicone, acrylic, etc.). In this case, the color conversion layer 104 may be attached between the first base film 101 and the second base film 102 .

For example, the color conversion layer 104 may include a red phosphor, a green phosphor, and inorganic particles according to a predetermined weight ratio. Here, the predefined weight ratio is a weight ratio between the weight of the red phosphor, the weight of the green phosphor, and the inorganic particles, which are determined based on the color coordinate value for white light.

Referring to FIG. 11 , the above-described color coordinate values for white light may be defined based on a Commission internationale de l'Eclairage (CIE) color space 110 . In this case, color coordinate values for white light may be defined as X coordinate values, Y coordinate values, and Z coordinate values defined in the color space 110 .

For example, the X coordinate value and the Y coordinate value may be defined in 0.27 to 0.33, and the Z coordinate value may be defined as a dependent variable based on the defined X coordinate and Y coordinate.

For example, the weight ratio of the red phosphor is defined within 10% to 80%, the weight ratio of the green phosphor is defined within 10% to 80%, and the weight ratio of the inorganic particles is defined within 1% to 10%. there is. In this case, of course, the total sum of the weight ratio of the red phosphor, the weight ratio of the green phosphor, and the weight ratio of the inorganic particles may be defined as 100% or less. Also, it goes without saying that when the weight ratio is not defined in %, the total sum of the weight ratios may be defined as 100 or less as well as more than 100.

Herein, an example in which the weight ratio of the red phosphor is greater than the weight ratio of the green phosphor and the weight ratio of the green phosphor is set to be greater than the weight ratio of the inorganic particles will be described below with reference to FIG. 12 .

12 shows a spectral spectrum measurement result according to an embodiment of the present invention.

In the embodiment of FIG. 12 , the ratio of the weight of the red phosphor, the weight of the green phosphor, and the weight of the inorganic particles included in the color conversion layer is set to 66:44:5. Here, the blue light emitted from the mini LED or micro LED is converted into white light while passing through the color conversion layer (or optical film). At the same time, light may be uniformly scattered to provide an appearance characteristic without mura ( 121 ).

The optical film 100 according to the above-described embodiment of FIG. 10 may further include an inorganic particle layer. This will be described below with reference to FIG. 13 . Hereinafter, content overlapping with the above-described optical film 100 will be omitted for convenience of description.

13 is a cross-sectional view of an optical film according to another embodiment of the present invention.

Referring to FIG. 13 , the optical film 130 may include a first base film 131 , a second base film 132 , a diffusion lens layer 133 , a color conversion layer 134 , and an inorganic particle layer 135 . can

The inorganic particle layer 135 may include the above-described inorganic particles. For example, the inorganic particle layer 135 may be formed by stirring the inorganic particles and the resin. In this case, the inorganic particle layer 135 may be attached to one surface of the first base film 131 .

In the above-described example, the inorganic particle layer 135 may further include the above-described red phosphor and green phosphor. In addition, the position of the inorganic particle layer 135 may be exchanged with the position of the color conversion layer 134 . In addition, the inorganic particle layer 135 may be attached to one surface of the second base film 132 .

14 is a cross-sectional view of an optical film according to another embodiment of the present invention.

Referring to FIG. 14 , the optical film 140 may include a first base film 141 , a second base film 142 , a diffusion lens layer 143 , a color conversion layer 144 , and an inorganic particle layer 145 . can Here, the inorganic particle layer 145 may be disposed on one side of the first base film 141 . Also, the diffusion lens layer 143 may be disposed on one surface of the inorganic particle layer 145 .

In various examples of the present invention described above, the optical film may further include a reflective pattern. Hereinafter, various embodiments including a reflective pattern will be described in detail.

15 is a cross-sectional view of an optical film according to another embodiment of the present invention.

Referring to FIG. 13 , the optical film 150 may include a first base film 151 , a second base film 152 , a diffusion lens layer 153 , a color conversion layer 154 , and a reflection pattern 155 . can

The reflective pattern 155 reflects light. The reflective pattern 155 may implement light recycling by reflecting light.

The reflective pattern 155 may be disposed or attached to at least one of one side of the first base film 151 or one side of the second base film 152 . For example, the reflective pattern 155 may be formed on one side of the first base film 151 or one side of the second base film 152 through a light/UV curing process. Here, the reflection pattern 155 may have a regular or irregular shape.

For example, the regions 155-1, 155-2, and 155-3 between the reflection patterns 155 correspond to the positions of the mini-LEDs or the positions of the micro-LEDs 156-1, 156-2, and 156-3. can be Specifically, the regions 155-1, 155-2, and 155-3 between the reflective pattern 155 may accommodate the mini-LED or micro-LED 156-1, 156-2, 156-3. .

Through this, it is possible to implement local dimming of individually controlling the mini LEDs or the micro LEDs 156-1, 156-2, and 156-3. Through local dimming, it is possible to adjust the light luminance. In addition, since the reflective pattern regions other than the regions 155 - 1 , 155 - 2 , and 155 - 3 between the reflective patterns 155 faithfully implement light reflection, the degree of light recycling may be increased.

For example, the regions 155-1, 155-2, and 155-3 between the reflective patterns 155 may contain a red phosphor, a green phosphor and It may contain inorganic particles. In this case, the optical film 150 may perform color conversion even without a separate color conversion tomography layer 154 .

16 is a cross-sectional view of an optical film according to another embodiment of the present invention.

Referring to FIG. 16 , the optical film 160 includes a first base film 161 , a second base film 162 , a diffusion lens layer 163 , a color conversion layer 164 , a reflective pattern 165 , and an inorganic particle layer. (166).

Here, the inorganic particle layer 166 may be disposed on one side of the first base film 161 . In this case, the diffusion lens layer 163 may be attached to one side of the inorganic particle layer 166 .

17 shows a performance test result of an optical film according to an embodiment of the present invention.

The performance experiment of the optical film of FIG. 17 is Rec. Based on the 2020 (UHDTV) standard, luminance (or luminance gain) was defined within 170% to 230% and color gamut below 61%.

In the first experiment 171, the optical film (eg, the optical film excluding the diffusion lens layer 103 in the optical film 100) includes a color conversion layer. Here, the light source is a mini LED or a micro LED, and an optical distance (OD) between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 205 μm, 100% luminance, 83% luminance uniformity, 54% color gamut, 0.0158 / 0.0399 color difference, and 0.2323 / 0.2162 for white x/y.

In the second experiment 172, the optical film (eg, the optical film 100) includes a color conversion layer and a diffusion lens layer. Here, the width of the square pyramid of the diffusion lens layer is set to 20 μm, the light source is a mini LED or micro LED, and the optical distance between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 255 μm, luminance 174%, luminance uniformity 83%, color gamut 57%, color difference 0.0158 / 0.0379, and white x/y 0.2503 / 0.2624.

In the third experiment 173, the optical film includes a color conversion layer, a diffusion lens layer, a diffusion sheet (eg, the diffusion sheet of FIG. 1) and a prism sheet (eg, the prism sheet of FIG. 1). Here, the width of the square pyramid of the diffusion lens layer is set to 20 μm, the light source is a mini LED or micro LED, and the optical distance between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 423 μm, luminance 215%, luminance uniformity 79%, color gamut 61%, color difference 0.0168 / 0.0379, and white x/y 0.2849 / 0.3433.

From the experimental results described above, since the optical film of the first experiment 171 includes a color conversion layer, high luminance (100%) and high luminance uniformity (83%) performance are realized. In addition, the optical film of the second experiment 172 further includes a diffusion lens layer in the optical film of the first experiment 171 to improve luminance (174%), improve color gamut (57%), and improve light distribution (first experiment) Refer to the light distribution diagram in (171), and realize the effect of condensing light through the light distribution) and improve spectral properties (reduction of the peak of white light intensity). In addition, the optical film of the third experiment 173 further includes a diffusion sheet and a prism sheet in the optical film of the second experiment 172 to improve luminance (215%), improve color gamut (61%), and improve light distribution (first 2, see the light distribution diagram of experiment 172), and improved spectral properties (reduction of the peak of white light intensity) are realized.

18 shows a performance test result of an optical film according to another embodiment of the present invention.

The performance experiment of the optical film of FIG. 18 is Rec. Based on the 2020 (UHDTV) standard, luminance (or luminance gain) was defined within 110% to 280% and color gamut below 58%.

In the first experiment 181, the optical film (eg, the optical film excluding the diffusion lens layer 103 in the optical film 100) includes a color conversion layer. Here, the light source is a mini LED or a micro LED, and an optical distance (OD) between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 200 μm, luminance 100%, luminance uniformity 73%, color gamut 46%, 9P color difference 0.0118 / 0.0322, and white x/y 0.2067 / 0.1651.

In the second experiment 182, the optical film (eg, the optical film 100) includes a diffusion lens layer and a color conversion layer. Here, the width of the square pyramid of the diffusion lens layer is 10 μm, the light source is a mini LED or micro LED, and the optical distance between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 288 μm, luminance 187%, luminance uniformity 76%, color gamut 52%, color difference 0.0128 / 0.0429, and white x/y 0.2251 / 0.2218.

In the third experiment 183, the optical film includes a diffusion lens layer, a color conversion layer, a diffusion sheet (eg, the diffusion sheet of FIG. 1) and a prism sheet (eg, the prism sheet of FIG. 1). Here, the width of the square pyramid of the diffusion lens layer is 10 μm, the light source is a mini LED or micro LED, and the optical distance between the light source and the optical film is set to 1 mm.

In this case, the laminate thickness of the light source and the optical film is measured to be 475 μm, luminance 236%, luminance uniformity 79%, color gamut 58%, color difference 0.0149 / 0.047, and white x/y 0.264 / 0.3118.

From the experimental results described above, since the optical film of the first experiment 181 includes a color conversion layer, high luminance (100%) and high luminance uniformity (73%) performance are realized. In addition, the optical film of the second experiment 182 further includes a diffusion lens layer in the optical film of the first experiment 171 to improve luminance (187%), improve color gamut (52%), improve luminance uniformity, and improve spectral properties (reducing the peak of white light intensity) is realized. In addition, the optical film of the third experiment 183 further includes a diffusion sheet and a prism sheet in the optical film of the second experiment 182 to improve luminance (236%), improve color gamut (58%), improve luminance uniformity, Photometric improvement (reducing the peak of white light intensity) is realized.

While the embodiments of the present invention have been shown and described, various changes in form and details may be made by those skilled in the art without departing from the spirit and scope of the embodiments as defined by the appended claims and their equivalents. you will understand that you can

Liquid crystal display: 1 Backlight unit: 10
Liquid crystal panel: 20 Light source: 11, 11'
Reflective sheet: 12 Color conversion sheet: 13
Diffusion lens sheet: 14
Diffusion lens layer: 32, 11-1, 12-1, 103, 133, 143, 153
Diffusion sheet: 15, 18 Prism sheet: 16, 17 Reflective polarizing sheet: 19
Optical film: 30, 60, 70, 100, 130, 140, 150
Base Film: 31, 31', 31'', 101, 102, 131, 132, 141, 142, 151, 152, 161, 162
Color conversion layer: 104, 134, 144, 154, 164
Inorganic particle layer: 135, 145, 166
Diffusion lens layer: 32, 11-1, 12-1, 103, 133, 143, 153, 163
Reflection Pattern: 155, 165

Claims (14)

In the optical film that transmits light emitted from a mini LED (light emitting diode) or micro LED,
a first base film; and
and a diffusion lens layer disposed on the first surface of the first base film and including a plurality of quadrangular pyramid-shaped lenses;
The diffusion lens layer is arranged so that the light is incident toward a second surface opposite to the first surface of the first base film,
The apex angle, which is an angle between two opposing surfaces among the four surfaces disposed on each of the plurality of quadrangular pyramid-shaped lenses, is 100° or more so that the light is refracted by the plurality of quadrangular pyramid-shaped lenses to form a separation angle. formed at 150° or less,
The plurality of quadrangular pyramid-shaped lenses include at least one first lens and at least one second lens forming a shape similar to each other,
The apex angle of the at least one first lens is equal to the apex angle of the at least one second lens,
A height of the at least one first lens is greater than a height of the at least one second lens, and an air gap is formed on the at least one second lens.
According to claim 1,
The separation angle is
Formed below 80°,
The separation angle is
The optical film is maximum when the apex angle is 105°.
The method of claim 1,
The incident angle of the light forms a right angle with one surface of the first base film, the optical film.
3. The method of claim 2,
The reverse-separation angle is formed when the light is incident in the one side direction of the first base film.
delete According to claim 1,
The height of the at least one of the plurality of quadrangular pyramid-shaped lenses is equal to the height of the other one of the plurality of quadrangular pyramid-shaped lenses.

ego,
Here, n is a natural number, the optical film.
According to claim 1,
The sizes and angles of the facing surfaces among the four surfaces disposed on the plurality of quadrangular pyramid-shaped lenses are the same as each other,
The sizes and angles of the connecting surfaces of the four surfaces disposed on the plurality of quadrangular pyramid-shaped lenses are different from each other, the optical film.
According to claim 1,
a second base film disposed parallel to the first base film; and
Further comprising; a color conversion layer disposed between the other surface of the first base film and one surface of the second base film;
Here, the color conversion layer,
An optical film comprising a red phosphor, a green phosphor, and inorganic particles inducing uniform scattering of the light according to a predefined weight ratio.
9. The method of claim 8,
The predefined weight ratio is
An optical film, wherein the X coordinate value and the Y coordinate value among the color coordinate values for white light are set to be 0.27 to 0.33.
10. The method of claim 9,
The color coordinate value for the white light is,
An optical film, which is an X coordinate value, a Y coordinate value and a Z coordinate value defined in the Commission internationale de l'Eclairage (CIE) color space.
9. The method of claim 8,
The weight ratio of the red phosphor is greater than the weight ratio of the green phosphor, the weight ratio of the green phosphor is greater than the weight ratio of the inorganic particles, the optical film.
9. The method of claim 8,
The weight ratio of the red phosphor is defined within 10% to 80%, the weight ratio of the green phosphor is defined within 10% to 80%, and the weight ratio of the inorganic particles is defined within 1% to 10%, optical film.
9. The method of claim 8,
The optical film further comprising; an inorganic particle layer comprising the inorganic particles.
9. The method of claim 8,
The other surface of the second base film is to arrange a plurality of reflective patterns, an optical film.

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