TWI860779B - Optical film and light-emitting module using the same - Google Patents

Abstract

An optical film and a light-emitting module using the same are provided. The light-emitting module includes a light-emitting assembly and an optical film. The light-emitting assembly includes a substrate and a plurality of light-emitting elements disposed on the substrate. The optical film disposed above the light-emitting elements and includes a base layer and a first optical structural layer disposed at one side thereof. The first optical structural layer includes a high refractive index layer and a low refractive index layer. An interface between the high and low refractive index layers includes a plurality of first inclined surfaces which is inclined relative to a thickness direction of the base layer.

Description

Optical film and light-emitting module using the same

The present invention relates to an optical film and a light-emitting module using the same, and in particular to an optical film used in a display device and a light-emitting module using the same.

At present, backlight modules have been widely used in display devices, especially liquid crystal display devices, to provide the light source required for displaying images. Existing backlight modules usually include a light-emitting component and an optical component disposed on the backlight source. The optical component can be used to adjust the light beam generated by the light-emitting component to make the brightness evenly distributed.

The light-emitting components in the backlight module usually use multiple light-emitting diodes (LEDs) or sub-millimeter light-emitting diodes (mini LEDs) arranged in an array, and the light beams they generate are concentrated and have high directivity. Therefore, to convert the point light source array generated by the light-emitting component into a surface light source, the optical component usually uses more optical films, such as light guides, diffusers, and brightness enhancement films, to use physical phenomena such as light refraction, reflection, or scattering to diffuse the light beams generated by the light-emitting component to the entire display area. However, this will result in the total thickness of the optical component cannot be further reduced.

The technical problem to be solved by the present invention is to provide a light-emitting module and an optical film applied thereto in view of the shortcomings of the existing technology. The optical film has a good diffusion effect on point light sources and can be applied to the light-emitting module of the display device.

In order to solve the above-mentioned technical problems, a technical solution adopted by the present invention is to provide a light-emitting module. The light-emitting module includes a light-emitting component and an optical film. The light-emitting component includes a substrate and a plurality of light-emitting units arranged on the substrate. The optical film is arranged on the light-emitting unit and includes a base layer and a first optical structure. The first optical structure is arranged on the base layer and includes a first high refractive index layer and a first low refractive index layer. The first high refractive index layer is located between the light-emitting component and the first low refractive index layer. The interface between the first high refractive index layer and the first low refractive index layer includes a plurality of first inclined planes, and each first inclined plane is inclined relative to the thickness direction of the base layer. The two connected first inclined surfaces jointly form a first angle, and the first angle satisfies the following relationship with the refractive index of the first high refractive index layer and the refractive index of the first low refractive index layer: θ1≦(180-2*arcsin(n10/n11)); wherein θ1 is the first angle, n11 is the refractive index of the first high refractive index layer, and n10 is the refractive index of the first low refractive index layer.

In order to solve the above technical problems, a technical solution adopted by the present invention is to provide an optical film. The optical film includes a substrate layer and a first optical structure. The first optical structure is arranged on a light incident side of the substrate layer and includes a first high refractive index layer and a first low refractive index layer. The first low refractive index layer is located between the first high refractive index layer and the substrate layer. The interface between the first high refractive index layer and the first low refractive index layer includes a plurality of first inclined surfaces, and each first inclined surface is inclined relative to the thickness direction of the substrate layer. The ratio between the refractive index of the first low refractive index layer and the refractive index of the first high refractive index layer ranges from 0.85 to 0.97.

One of the beneficial effects of the present invention is that the optical film and the light-emitting module using the optical film provided by the present invention can diffuse the light beam generated by the light-emitting component through the technical solutions of "the optical film is arranged on a plurality of light-emitting units and includes a base layer and a first optical structure", "the first optical structure includes a first high refractive index layer and a first low refractive index layer, and the first high refractive index layer is located between the light-emitting component and the first low refractive index layer", and "the interface between the first high refractive index layer and the first low refractive index layer includes a plurality of first inclined surfaces, and each first inclined surface is inclined relative to the thickness direction of the base layer".

To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description and are not used to limit the present invention.

Z1-Z8: Light-emitting module

1: Light-emitting components

10: Substrate

100: Base plate

101:Reflective layer

101s: Reflective surfaces

11: Light-emitting unit

12,12’: Packaging layer

2A-2F,2B’: Optical film

20: Basal layer

20a: First surface

20b: Second surface

21: First optical structure

210: First low refractive index layer

210A, 220A: Concave microstructure

21L: First Ridge

211: First high refractive index layer

211s: light-entering surface

211A, 221A: protruding microstructure

S1: First slope

θ1: first angle

L1: First initial beam

L11, L13, L16, L17: First reflected beam

L12, L14, L15, L18: First transmitted beam

L2: Second initial beam

L21: Second total reflection beam

L22, L24, L26: Second transmitted beam

L23, L25, L27: Second reflected beam

22: Second optical structure

220: The second highest refractive index layer

221: Second low refractive index layer

221s: External surface

22L: Second ridge

S2: Second slope

θ2: Second angle

θ: vertex angle

222: The third highest refractive index layer

S3: The third slope

θ3: The third angle

b1: Bubbles

P1: Nanoparticles

d1: first spacing

d2: Second spacing

d3: third distance

D1: First direction

D2: Second direction

G1: Gap

Figure 1 is a partial side view schematic diagram of the light-emitting module of the first embodiment of the present invention.

Figure 2A is a partial enlarged schematic diagram of area IIA in Figure 1.

Figure 2B is a partial enlarged schematic diagram of area IIA in Figure 1.

Figure 3 is a partial three-dimensional exploded schematic diagram of the first optical structure of an embodiment of the present invention.

Figure 4 is a partially enlarged schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 5 is a partial side view schematic diagram of the light-emitting module of the second embodiment of the present invention.

Figure 6 is a partial enlarged schematic diagram of area VI in Figure 5.

Figure 7 is a partial three-dimensional exploded schematic diagram of an optical film according to an embodiment of the present invention.

Figure 8 is a partial three-dimensional exploded schematic diagram of an optical film of another embodiment of the present invention.

Figure 9 is a partially enlarged schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 10 is a partially enlarged schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 11 is a partially enlarged schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 12 is a partial side view schematic diagram of the light-emitting module of the third embodiment of the present invention.

Figure 13 is a partial side view schematic diagram of the light-emitting module of the fourth embodiment of the present invention.

Figure 14 is a partial side view schematic diagram of the light-emitting module of the fifth embodiment of the present invention.

Figure 15 is a partial side view schematic diagram of the light-emitting module of the sixth embodiment of the present invention.

Figure 16 is a partial three-dimensional exploded view of the optical film in Figure 15.

Figure 17 is a partial side view schematic diagram of the light-emitting module of the seventh embodiment of the present invention.

Figure 18 is a partial side view schematic diagram of the light-emitting module of the eighth embodiment of the present invention.

The following is a specific embodiment to illustrate the implementation of the "optical film and the light-emitting module using the same" disclosed in the present invention. The technical personnel in this field can understand the advantages and effects of the present invention from the content disclosed in this manual. The present invention can be implemented or applied through other different specific embodiments, and the details in this manual can also be modified and changed based on different viewpoints and applications without deviating from the concept of the present invention. In addition, the attached drawings of the present invention are only for simple schematic illustrations and are not depicted according to actual sizes. Please note in advance. The following implementation will further explain the relevant technical content of the present invention in detail, but the disclosed content is not used to limit the scope of protection of the present invention.

It should be understood that although the terms "first", "second", "third" and so on may be used in this article to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" used in this article may include any one or more combinations of the related listed items depending on the actual situation.

Please refer to FIG. 1 and FIG. 2A. FIG. 1 is a partial side view schematic diagram of the light-emitting module of the first embodiment of the present invention, and FIG. 2A is a partial enlarged schematic diagram of area IIA in FIG. 1. The light-emitting module Z1 can be applied to the backlight module of the display device, such as: a direct-type backlight module, to evenly diffuse the light source to a specific display area.

The light-emitting module Z1 includes a light-emitting component 1 and an optical film 2A. The light-emitting component 1 includes a substrate 10 and a plurality of light-emitting units 11 disposed on the substrate 10. The substrate 10 has a reflective surface 101s for reflecting light beams, and the plurality of light-emitting units 11 are disposed on the reflective surface 101s. Further, the substrate 10 of the present embodiment includes a bottom plate 100 and a reflective layer 101 disposed on the bottom plate 100, and the plurality of light-emitting units 11 are disposed on the reflective layer 101, but the present invention is not limited thereto. The bottom plate 100 is, for example, a ceramic bottom plate, a metal bottom plate or a composite bottom plate, and the present invention is not limited thereto. The reflective layer 101 is, for example, a metal coating or coated with reflective white glue to reflect the light beams generated by the plurality of light-emitting units 11.

A plurality of light-emitting units 11 are disposed on the substrate 10 and arranged in an array to generate a point light source or a line light source. In addition, each light-emitting unit 11 may be a micro LED or a sub-millimeter LED, but the present invention is not limited thereto. In addition, in the present embodiment, the light-emitting component 1 further includes a packaging layer 12, and the packaging layer 12 covers each light-emitting unit 11 to protect the light-emitting unit 11.

The optical film 2A is disposed on a plurality of light-emitting units 11 adjacent to the light-emitting component 1. In this embodiment, the optical film 2A is directly disposed on the packaging layer 12 of the light-emitting component 1, but the present invention is not limited thereto. In another embodiment, the optical film 2A may also be spaced a predetermined distance from the light-emitting component 1.

The optical film 2A can evenly diffuse the light beam generated by the light-emitting unit 11. Furthermore, the optical film 2A can be used as a diffusion sheet or a brightness enhancement sheet to convert a point light source or a line light source into a surface light source. As shown in FIG1 , the optical film 2A provided in the embodiment of the present invention includes a base layer 20 and a first optical structure 21. In one embodiment, the total thickness of the optical film 2A can be from 40 μm to 300 μm.

Furthermore, the optical film 2A has a light incident side and a light exiting side opposite to the light incident side. The first optical structure 21 can be located on the light incident side or the light exiting side of the optical film 2A. In this embodiment, the first optical structure 21 is located on the light incident side of the optical film 2A.

Further, the base layer 20 has a first surface 20a and a second surface 20b opposite to the first surface 20a. In the present embodiment, the first surface 20a of the base layer 20 faces the light-emitting component 1. In the present embodiment, the first optical structure 21 is disposed on the first surface 20a and is located on the light-incident side of the base layer 20. However, in another embodiment, the first optical structure 21 may also be disposed on the second surface 20b. In the present embodiment, the thickness of the first optical structure 21 ranges from 5um to 100um.

In addition, the material constituting the base layer 20 may be polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), acrylic (PMMA), acrylic acid (MMA), etc. As long as the material constituting the base layer 20 allows the light beam to pass through, the present invention is not limited. In addition, the thickness of the base layer 20 may be from 30μm to 250μm, preferably from 50μm to 125μm, which is easier to process.

In this embodiment, the first optical structure 21 includes a first low refractive index layer 210 and a first high refractive index layer 211. The first high refractive index layer 211 is located between the first low refractive index layer 210 and the light-emitting component 1. Accordingly, the first high refractive index layer 211 has a light incident surface 211s facing the light-emitting component 1. In addition, the first high refractive index layer 211 completely covers the first low refractive index layer 210. In this embodiment, the light incident surface 211s of the first high refractive index layer 211 is a flat surface and is directly connected to the packaging layer 12 of the light-emitting component 1, but the present invention is not limited thereto.

That is to say, the light beams generated by the multiple light-emitting units 11 will enter the optical film 2A from the light-incident surface 211s of the first high-refractive-index layer 211, then pass through the first low-refractive-index layer 210 and the base layer 20, and be emitted from the second surface 20b of the base layer 20.

In addition, in this embodiment, the refractive index of the base layer 20 is lower than the refractive index of the first high refractive index layer 211, but higher than the refractive index of the first low refractive index layer 210. In addition, in this embodiment, the refractive index of the packaging layer 12 of the light-emitting component 1 is lower than the refractive index of the first high refractive index layer 211. For example, the refractive index of the packaging layer 12 can be 1.48, the refractive index of the first high refractive index layer 211 can be 1.61, the refractive index of the first low refractive index layer 210 can be 1.45, and the refractive index of the base layer 20 can be 1.57, but the present invention is not limited thereto.

Please refer to FIG. 2A , it should be noted that the interface between the first high refractive index layer 211 and the first low refractive index layer 210 includes a plurality of first inclined surfaces S1, and each first inclined surface S1 is inclined relative to the thickness direction of the base layer 20. In this embodiment, every two connected first inclined surfaces S1 together form a first angle θ1.

In this embodiment, the first angle θ1, the refractive index of the first high refractive index layer 211, and the refractive index of the first low refractive index layer 210 satisfy the following relationship: θ1≦(180-2*arcsin(n10/n11)); wherein θ1 is the first angle, n11 is the refractive index of the first high refractive index layer 211, and n10 is the refractive index of the first low refractive index layer 210. Thus, most of the light beams generated by the light-emitting unit 11 are initially projected onto the first inclined surface S1 at an angle greater than the critical angle of total reflection and are totally reflected. By making the first angle θ1 formed by the two connected first inclined surfaces S1 smaller than a specific value, the light beam generated by the light emitting unit 11 that enters the first optical structure 21 and projects onto the first inclined surface S1 at an angle within 10 degrees relative to the optical axis of the light emitting unit 11 can be totally reflected.

In addition, in a preferred embodiment, the ratio R (R=n10/n11) between the refractive index n10 of the first low refractive index layer 210 and the refractive index n11 of the first high refractive index layer 211 is 0.85 to 0.97, which can make the optical film 2A have a better light diffusion effect. It should be noted that when the ratio R is higher than 0.97, the optical refraction effect is poor. In addition, when the ratio R is less than 0.85, the material of the first low refractive index layer 210 needs to be a fluorine-containing material. However, the fluorine-containing first low refractive index layer 210 and the commonly used materials of the first high refractive index layer 211, such as polymethyl methacrylate (PMMA), are difficult to combine and have poor matching.

It should be noted that when a light beam enters a medium with a higher refractive index (the first high refractive index layer 211) into a medium with a lower refractive index (the first low refractive index layer 210), and the incident angle of the light beam is greater than the critical angle, the light beam will be totally reflected. Conversely, when a light beam enters a medium with a higher refractive index from a medium with a lower refractive index, the light beam will not be totally reflected, but will be divided into refracted light and reflected light.

Therefore, by placing the first high refractive index layer 211 between the first low refractive index layer 210 and the light-emitting component 1, the probability of the light beam being totally reflected in the optical film 2A can be increased. On the other hand, since the refractive index of the base layer 20 is higher than that of the first low refractive index layer 210, the light beam will not be totally reflected after entering the base layer 20 from the first low refractive index layer 210.

As shown in FIG2A, the first initial light beam L1 generated by a single light-emitting unit 11 is used as an example for explanation, but the light beam generated by the light-emitting unit 11 is not limited thereto. In addition, in order to facilitate the explanation of the path of the light beam in the optical film 2A, some refracted light beams or some reflected light beams are not shown in FIG2A.

When the first initial light beam L1 is projected onto the interface between the packaging layer 12 and the first high refractive index layer 211 (that is, the light incident surface 211s of the first high refractive index layer 211), a first reflected light beam L11 and a first transmitted light beam L12 are formed. The first reflected light beam L11 is projected onto the reflective surface 101s of the light-emitting component 1 and then reflected into the first optical structure 21.

The incident angle of the first transmitted light beam L12 projected onto the first inclined surface S1 is less than the critical angle of total reflection, so another first reflected light beam L13 and a first transmitted light beam L14 entering the first low refractive index layer 210 are formed on the first inclined surface S1. The first transmitted light beam L14 is emitted after passing through the base layer 20. The first reflected light beam L13 is projected onto another first inclined surface S1 at an angle less than the critical angle of total reflection, and is further divided into a first transmitted light beam L15 and a first reflected light beam L16. It is worth noting that the incident angle of the first reflected light beam L16 projected onto another first inclined surface S1 is greater than the critical angle of total reflection, and can be totally reflected.

After the first transmitted light beam L15 is projected onto the first low refractive index layer 210, it is further divided into the first transmitted light beam L18 and the first reflected light beam L17. The first transmitted light beam L18 is emitted through the base layer 20 and projected outside the optical film 2A. The first reflected light beam L17 can continue to pass through refraction, reflection and total reflection, and is transmitted between the first low refractive index layer 210 and the first high refractive index layer 211.

In addition, please refer to FIG. 2B , which takes the second initial light beam L2 generated by a single light-emitting unit 11 as an example. Similarly, in order to facilitate the description of the path of the light beam in the optical film 2A, some refracted light beams or some reflected light beams are not shown in FIG. 2B . The second initial light beam L2 enters the first high refractive index layer 211 perpendicular to the light incident surface 211s, and then projects onto the first inclined surface S1. Since the incident angle of the second initial light beam L2 projected onto the first inclined surface S1 is greater than the critical angle of total reflection, it will be totally reflected to form a second totally reflected light beam L21, and will not directly enter the first low refractive index layer 210.

After the second total reflection light beam L21 is projected onto another first inclined surface S1, it is further divided into a second transmission light beam L22 and a second reflection light beam L23. After the second transmission light beam L22 is projected onto the first surface 20a of the base layer 20, it is divided into a second transmission light beam L24 and a second reflection light beam L25. The second transmission light beam L24 is emitted after passing through the base layer 20, and another part of the second reflection light beam L25 is further dispersed by reflection, refraction or total reflection in the first optical structure 21.

In addition, the second reflected light beam L23 is reflected to the first inclined surface S1 and is divided into another second transmitted light beam L26 and another second reflected light beam L27. The second transmitted light beam L26 is transmitted in the first optical structure 21 by multiple refractions, reflections or total reflections, and travels back and forth between the first high refractive index layer 211 and the first low refractive index layer 210 for multiple times.

Therefore, the second reflected light beam L23 is refracted, reflected or totally reflected multiple times at the interface between the first low refractive index layer 210 and the first high refractive index layer 211, and can be transmitted laterally for a certain distance in the first optical structure 21. The second reflected light beam L27 is projected onto the first inclined surface S1 at an incident angle greater than the critical angle of total reflection, and is totally reflected. In addition, it should be noted that most of the light beams entering the optical film 2A enter the first high refractive index layer 211 nearly perpendicular to the light incident surface 211s, such as the second initial light beam L2, and are diffused by refraction, reflection or total reflection. Accordingly, the optical film 2A provided in this embodiment can effectively diffuse the point light source generated by the light-emitting component 1.

The surface profile of the first low refractive index layer 210 and the surface profile of the first high refractive index layer 211 can be matched with each other. The first low refractive index layer 210 has a plurality of microstructures, each of which can be a triangular prism, a trapezoidal prism, an arcuate prism, a convex pyramid, a concave pyramid or other prisms, but the present invention is not limited thereto.

Please refer to FIG. 3, which is a partial three-dimensional exploded schematic diagram of the first optical structure of an embodiment of the present invention. In this embodiment, the first low refractive index layer 210 has a plurality of concave microstructures 210A, and the first high refractive index layer 211 is filled with the plurality of concave microstructures 210A. In detail, the first low refractive index layer 210 having a plurality of concave microstructures 210A can be first manufactured, and then a glue having a high refractive index is filled into the plurality of concave microstructures 210A to form the first high refractive index layer 211. Therefore, the first high refractive index layer 211 will have a plurality of convex microstructures 211A.

Accordingly, the shapes of the concave microstructure 210A of the first low refractive index layer 210 and the convex microstructure 211A of the first high refractive index layer 211 are matched with each other. In this embodiment, the concave microstructure 210A is a concave pyramid microstructure, and the convex microstructure 211A is a convex pyramid microstructure. The concave microstructure 210A may include four interconnected triangular inclined surfaces, and the four triangular inclined surfaces are connected to each other so that the concave microstructure 210A has a closed opening end, which helps to make the light beam entering the first optical structure 21 be reflected and refracted more times. In another embodiment, each concave microstructure 210A (or convex microstructure 211A) may also have three triangular inclined surfaces, but the present invention is not limited thereto.

When the light beam generated by one of the light-emitting units 11 enters the first optical structure 21, it can be transmitted laterally for a certain distance in the first optical structure 21 through multiple reflections and refractions before entering the base layer 20. In this way, the light-homogenizing effect of the optical film 2A can be increased.

Please refer to FIG. 4, which is a partial side view schematic diagram of a light-emitting module of another embodiment of the present invention. The same components as the light-emitting module Z1 of the previous embodiment have the same reference numerals, and the same parts are not repeated. The first optical structure 21 of the present embodiment has a plurality of bubbles b1. Specifically, at least one of the first low refractive index layer 210 and the first high refractive index layer 211 has a plurality of bubbles b1 randomly dispersed therein.

In one embodiment, the plurality of bubbles b1 are microbubbles or ultrafine bubbles. Furthermore, at least 90% of the bubbles b1 have a bubble diameter less than 10 μm, preferably less than 1 μm. Accordingly, the average bubble diameter of the plurality of bubbles b1 will also be less than 10 μm, preferably less than 1 μm. Since the shape of the bubble b1 is not necessarily circular, in the present invention, "the bubble diameter of the bubble b1" refers to the average value of the maximum diameter and the minimum diameter of the individual bubble b1. In addition, "average bubble diameter" refers to the average of the bubble diameters of all bubbles b1.

Furthermore, the (area) distribution density of the plurality of bubbles b1 is greater than or equal to 100/ ^mm2 . In addition, the volume distribution density of the plurality of bubbles b1 is at least 1000/ ^mm3 . The medium filled in the plurality of bubbles b1 may be air, nitrogen, helium, neon, carbon dioxide or any combination thereof. However, in another embodiment, the first high refractive index layer 211 may also have a plurality of dispersed bubbles b1, while the first low refractive index layer 210 and the base layer 20 may have almost no bubbles. In yet another embodiment, both the first low refractive index layer 210 and the first high refractive index layer 211 may have bubbles b1.

It should be noted that when a light beam enters a light-dense medium (optical film 2A) from a light-sparse medium (air), the refraction angle of the light beam will be smaller than the incident angle. On the contrary, when a light beam enters a light-dense medium from a light-dense medium, the refraction angle of the light beam will be larger than the incident angle. Since the first optical structure 21 has a plurality of air bubbles b1 distributed at a high density inside, the first optical structure 21 will have different transmission media for the light beam. Therefore, when the light beam is transmitted in the first optical structure 21, it is easy to refract, reflect and scatter at multiple angles and directions between different medium interfaces, thereby further enhancing the effect of diffusing the light beam.

Please refer to Figures 5 and 6. Figure 5 is a partial side view schematic diagram of the light-emitting module of the second embodiment of the present invention, and Figure 6 is a partial enlarged schematic diagram of area VI in Figure 5. The light-emitting module Z2 of this embodiment has the same components as the light-emitting module Z1 of the previous embodiment, and the same parts are not repeated.

The optical film 2B of this embodiment includes a base layer 20, a first optical structure 21 and a second optical structure 22. The first optical structure 21 and the second optical structure 22 are respectively located on opposite sides of the base layer 20. Specifically, the second optical structure 22 is located on the second surface 20b of the base layer 20, that is, the light-emitting side of the optical film 2B. In this embodiment, the refractive index of the second optical structure 22 is greater than the refractive index of air (1.33).

As shown in FIG. 5 and FIG. 6 , the surface of the second optical structure 22 includes a plurality of second inclined surfaces S2, and a second angle θ2 is formed between each two connected second inclined surfaces S2. In this embodiment, the second angle θ2 may be greater than or equal to the first angle θ1. In detail, the second optical structure 22 includes a plurality of microstructures, each of which may be a triangular prism, a trapezoidal prism, an arcuate prism, a semicircular prism, a convex pyramid, a concave pyramid, a pyramidal prism or a semispherical prism, and the present invention is not limited thereto.

As shown in FIG. 5 , in this embodiment, the first spacing d1 between any two microstructures of the first low refractive index layer 210 may be less than or equal to the second spacing d2 between any two microstructures of the second optical structure 22. In addition, the cross-sectional width of the microstructure of the second optical structure 22 may be greater than or equal to the cross-sectional width of the microstructure of the first low refractive index layer 210.

Please refer to FIG. 7, which shows a partial three-dimensional schematic diagram of an optical film of an embodiment of the present invention. In the embodiment shown in FIG. 7, the plurality of convex microstructures (such as triangular prisms, semi-circular prisms or polygonal prisms) of the second optical structure 22 extend along the second direction D2, but the present invention is not limited to this example. In addition, the plurality of convex microstructures (such as triangular prisms, semi-circular prisms or polygonal prisms) of the first low refractive index layer 210 are arranged side by side in the first direction D1 and extend along the second direction D2, but the present invention is not limited to this.

In this embodiment, each convex column microstructure of the first low refractive index layer 210 is an inverted triangular column and has a first ridge 21L. Each convex column microstructure of the second optical structure 22 is a triangular column and has a second ridge 22L, and the first ridge 21L and the second ridge 22L have the same extension direction (second direction D2).

Please refer to FIG. 8, which shows a partial three-dimensional schematic diagram of an optical film of another embodiment of the present invention. In the optical film 2B' of this embodiment, the first low refractive index layer 210 includes a plurality of first convex column microstructures, and the second optical structure 22 includes a plurality of second convex column microstructures, but the first convex column microstructures and the second convex column microstructures have different extension directions. In one embodiment, the angle formed between the extension directions of the first convex column microstructure of the first low refractive index layer 210 and the second convex column microstructure of the second optical structure 22 ranges from 45 degrees to 90 degrees, preferably 80 to 90 degrees.

The first low refractive index layer 210 has a plurality of first convex column microstructures arranged side by side in the second direction D2, and each first convex column microstructure extends along the first direction D1. However, the second optical structure 22 has a plurality of second convex column microstructures arranged side by side in the first direction D1, and each second convex column microstructure extends along the second direction D2.

As shown in FIG8 , for example, each first convex microstructure of the first low refractive index layer 210 is an inverted triangular prism and has a first ridge 21L. Each second convex microstructure of the second optical structure 22 is a triangular prism and has a second ridge 22L. The angle formed between the extension direction of the first ridge 21L and the extension direction of the second ridge 22L can range from 45 degrees to 90 degrees. Compared with the optical film 2B shown in FIG7 , the optical film 2B' shown in FIG8 can have a more uniform light diffusion effect.

Please refer to FIG. 9, which shows a partial enlarged schematic diagram of the light-emitting module of different embodiments of the present invention. The same or similar components of the embodiment shown in FIG. 9 and the embodiment of FIG. 6 have the same reference numerals, and the same parts will not be repeated.

At least one of the second optical structure 22, the first low refractive index layer 210 and the first high refractive index layer 211 has a plurality of bubbles b1 and a plurality of nanoparticles P1 randomly dispersed therein, and at least one nanoparticle P1 is combined with one of the bubbles b1. In this embodiment, the first high refractive index layer 211 is used as an example for illustration. As mentioned above, the plurality of bubbles b1 may include microbubbles, ultrafine bubbles or a mixture thereof. Furthermore, at least 90% of the bubbles b1 have a bubble diameter less than 10 μm, preferably less than 1 μm.

In addition, in this embodiment, a portion of the nanoparticles P1 will be combined with the corresponding bubbles b1. After the nanoparticles P1 are combined with the corresponding bubbles b1, the bubbles b1 combined with the nanoparticles P1 will not dissolve in the colloid, ensuring the existence of the bubbles b1. In detail, the nanoparticles P1 combined with the bubbles b1 are usually close to the edge of the bubbles b1 and located inside the bubbles b1, but the present invention is not limited to this. A small number of nanoparticles P1 combined with the bubbles b1 are located outside the bubbles b1, but still close to the edge of the bubbles b1.

It should be noted that not all nanoparticles P1 will be combined with bubbles b1. In other words, some bubbles b1 will be individually dispersed in the first high refractive index layer 211. On the other hand, some nanoparticles P1 that are not combined with bubbles b1 will be individually dispersed in the first high refractive index layer 211. In addition, in the present invention, it is not limited that a bubble b1 is combined with only one nanoparticle P1, and it is also possible that a bubble b1 is combined with two or more nanoparticles P1.

In one embodiment, among a plurality of nanoparticles P1, 90% of the nanoparticles P1 have a particle size of no more than 100 nm, preferably 30 nm to 50 nm. Accordingly, the average particle size of the nanoparticles P1 does not exceed 100 nm, preferably 30 nm to 50 nm. In the present invention, "the particle size of the nanoparticles P1" refers to the average value of the maximum diameter and the minimum diameter of the individual nanoparticles P1.

In addition, "the average particle size of the nanoparticles P1" refers to the average particle size of all nanoparticles P1. In addition, the nanoparticles P1 can be nanometal, nanooxide or nanodiamond. In the best embodiment, the material of the nanoparticles P1 is silicon dioxide or titanium dioxide. The first optical structure 21 includes a plurality of nanoparticles P1 dispersed therein, which can also enhance the light diffusion effect.

Referring to FIG. 10 , in an optical film 2B of another embodiment of the present invention, at least one of the second optical structure 22, the first low refractive index layer 210, and the first high refractive index layer 211 may have a plurality of bubbles b1 randomly dispersed therein. In this embodiment, the second optical structure 22 having bubbles b1 is used as an example for explanation. In each microstructure of the second optical structure 22, the volume distribution density (number per unit volume) of the plurality of bubbles b1 decreases from the top of the microstructure of the second optical structure 22 toward the base layer 20.

Furthermore, the portion of the microstructure of the second optical structure 22 above half the height is defined as the upper half of the microstructure, and the portion of the microstructure of the second optical structure 22 below half the height is defined as the lower half of the microstructure of the second optical structure 22. Accordingly, the volume distribution density of the plurality of bubbles b1 in the upper half of each microstructure of the second optical structure 22 is greater than the volume distribution density in the lower half.

Please refer to FIG. 11 . In another embodiment of the optical film 2B of the present invention, the second optical structure 22 may have a plurality of bubbles b1 and a plurality of nanoparticles P1, and at least one nanoparticle P1 is combined with the bubble b1 to enhance the light diffusion effect. The bubble diameter range of the bubble b1 and the particle diameter and material of the nanoparticle P1 have been described in the previous text and will not be repeated here.

Please refer to FIG. 12, which shows a partial side view schematic diagram of the light-emitting module of the third embodiment of the present invention. The light-emitting module Z3 of this embodiment has the same components as the light-emitting module Z2 of the second embodiment, and the same parts are not repeated. The difference between this embodiment and the second embodiment is that the optical film 2B and the light-emitting component 1 are separated from each other. That is, a gap G1 is defined between the optical film 2B and the packaging layer 12 of the light-emitting component 1, and the gap G1 can be filled with air.

Furthermore, the light incident surface 211s of the first high refractive index layer 211 will not be closely attached to the packaging layer 12 of the light-emitting component 1. Since the difference between the refractive index of air and the refractive index n10 of the first high refractive index layer 211 is relatively large, it helps to diffuse the light beam.

Please refer to Figure 13, which is a partial side view schematic diagram of the light-emitting module of the fourth embodiment of the present invention. The light-emitting module Z4 of this embodiment has the same components as the light-emitting module Z3 of the third embodiment, and the same parts are not repeated. In this embodiment, the packaging layer 12' of the light-emitting component 1 does not completely cover the reflective surface 101s of the substrate 10. Furthermore, the packaging layer 12' includes a plurality of separated parts, and each part covers the corresponding light-emitting unit 11.

In addition, the optical film 2A and the light-emitting component 1 are also separated from each other to define a gap G1, and the gap G1 can be filled with air, but the present invention is not limited to this example. In another embodiment, the optical film 2A can also partially contact the packaging layer 12'. That is, multiple gaps can be defined between the light incident surface 211s of the first high refractive index layer 211 and the packaging layer 12'.

Please refer to Figure 14, which is a partial side view schematic diagram of the light-emitting module of the fifth embodiment of the present invention. The light-emitting module Z5 of this embodiment has the same components as the light-emitting module Z2 of the second embodiment, and the same parts are not repeated.

In this embodiment, the optical film 2C includes a base layer 20, a first optical structure 21 and a second optical structure 22. The second optical structure 22 includes a second high refractive index layer 220 and a second low refractive index layer 221. The second high refractive index layer 220 is located between the second low refractive index layer 221 and the base layer 20. That is, in this embodiment, the light beam after passing through the base layer 20 will first enter the second high refractive index layer 220 and then enter the second low refractive index layer 221. When the incident angle of the light beam incident on the interface between the second high refractive index layer 220 and the second low refractive index layer 221 is greater than the critical angle of total reflection, the light beam will also be totally reflected. Accordingly, the light beam will also be refracted and reflected multiple times in the second optical structure 22 and transmitted laterally, so that the optical film 2C has a better light diffusion effect.

The refractive index of the second high refractive index layer 220 is higher than the refractive index of the second low refractive index layer 221. In addition, the surface profile of the second high refractive index layer 220 will match the surface profile of the second low refractive index layer 221. The interface between the second high refractive index layer 220 and the second low refractive index layer 221 includes a plurality of second inclined surfaces S2, each of which is inclined relative to the thickness direction of the base layer 20.

As shown in FIG. 14 , the second high refractive index layer 220 has a plurality of microstructures. The second spacing d2 between two adjacent microstructures of the second high refractive index layer 220 is greater than the first spacing d1 between two adjacent microstructures of the first low refractive index layer 210, but the present invention is not limited thereto. In addition, the second low refractive index layer 221 covers the second high refractive index layer 220 and has an outer surface 221s. In this embodiment, the outer surface 221s is the light emitting surface of the optical film 2C and is a flat surface.

In this embodiment, by placing the second high refractive index layer 220 of the second optical structure 22 between the base layer 20 and the second low refractive index layer 221, the number of times the light beam projected onto the second inclined surface S2 is totally reflected can be increased, so that the light beam is transmitted laterally in the second optical structure 22. In this way, the light diffusion effect of the optical film 2C can be further enhanced.

Please refer to FIG. 15 and FIG. 16. FIG. 15 is a partial side view schematic diagram of the light-emitting module of the sixth embodiment of the present invention, and FIG. 16 is a partial three-dimensional exploded view of the optical film of FIG. 15. The light-emitting module Z6 of this embodiment has the same components as the light-emitting module Z5 of the fifth embodiment, and the same parts are not repeated. As shown in FIG. 15, the optical film 2D, the second high refractive index layer 220 has a plurality of microstructures. The second spacing d2 between two adjacent microstructures of the second high refractive index layer 220 will be equal to the first spacing d1 between two adjacent microstructures of the first low refractive index layer 210, but the present invention is not limited thereto.

Please refer to FIG. 16 , in detail, the first low refractive index layer 210 includes a plurality of concave microstructures 210A. The first high refractive index layer 211 is filled into the plurality of concave microstructures 210A to form a plurality of convex microstructures 211A, and the shapes of the convex microstructures 211A and the concave microstructures 210A match each other. In this embodiment, the concave microstructure 210A is a concave pyramid microstructure, and the convex microstructure 211A is a convex pyramid microstructure. Each concave microstructure 210A (or convex microstructure 211A) of this embodiment has four interconnected first inclined surfaces S1, and each first inclined surface S1 is a triangular inclined surface, but the present invention is not limited thereto. In another embodiment, each recessed microstructure 210A (or protruding microstructure 211A) may also have only three interconnected first inclined surfaces S1.

As shown in FIG16 , the top angle of at least one triangular inclined surface and the refractive index of the first high refractive index layer 211 and the refractive index of the first low refractive index layer 210 satisfy the following relationship: θ≦(180-2*arcsin(n10/n11)); wherein θ is the top angle of the triangular inclined surface, n11 is the refractive index of the first high refractive index layer 211, and n10 is the refractive index of the first low refractive index layer 210. In this way, the light beam entering the first optical structure 21 is reflected and refracted more times.

Different from the first optical structure 21, the second high refractive index layer 220 of the second optical structure 22 includes a plurality of concave microstructures 220A, and the second low refractive index layer 221 is filled with a plurality of concave microstructures 220A to form a plurality of convex microstructures 221A. The concave microstructure 220A may be a concave pyramid microstructure, and the convex microstructure 221A may be a convex pyramid microstructure. Accordingly, the shapes of each concave microstructure 220A of the second high refractive index layer 220 and each convex microstructure 221A of the second low refractive index layer 221 are matched with each other. Further, each concave microstructure 220A of the second high refractive index layer 220 has four second inclined surfaces S2 connected to each other, and each second inclined surface S2 is a triangular inclined surface, but the present invention is not limited thereto. In another embodiment, each recessed microstructure 220A of the second high refractive index layer 220 may also have only three interconnected second inclined surfaces S2.

Please refer to Figure 17, which is a partial side view schematic diagram of the light-emitting module of the seventh embodiment of the present invention. The light-emitting module Z7 of this embodiment has the same components as the light-emitting module Z5 of the fifth embodiment, and the same parts will not be repeated.

In this embodiment, the second optical structure 22 of the optical film 2E includes a second high refractive index layer 220, a second low refractive index layer 221, and a third high refractive index layer 222. The second low refractive index layer 221 is located between the second high refractive index layer 220 and the third high refractive index layer 222. It is worth mentioning that the interface between the second high refractive index layer 220 and the second low refractive index layer 221 includes a plurality of second inclined surfaces S2, but the interface between the second low refractive index layer 221 and the third high refractive index layer 222 is a flat surface.

In this embodiment, the surface of the third high refractive index layer 222 includes a plurality of third inclined surfaces S3, and a third angle θ3 is formed between every two connected third inclined surfaces S3. In this embodiment, the second angle θ2 formed between two connected second inclined surfaces S2 is less than or equal to the third angle θ3.

In addition, each microstructure of the second high refractive index layer 220 and each microstructure of the third high refractive index layer 222 have different cross-sectional widths. The second distance d2 between any two adjacent microstructures of the second high refractive index layer 220 is less than or equal to the third distance d3 between any two adjacent microstructures of the third high refractive index layer 222.

Please refer to Figure 18, which is a partial side view schematic diagram of the light-emitting module of the eighth embodiment of the present invention. The light-emitting module Z8 of this embodiment has the same components as the light-emitting module Z5 of the fifth embodiment, and the same parts will not be repeated.

In this embodiment, the first optical structure 21 and the second optical structure 22 of the optical film 2F are respectively located on the light incident side (first surface 20a) and the light emitting side (second surface 20b) of the base layer 20. In this embodiment, the light incident surface 211s of the first high refractive index layer 211 of the first optical structure 21 and the outer surface 221s (light emitting surface) of the second low refractive index layer 221 of the second optical structure 22 are not flat surfaces, but have multiple concave microstructures.

In detail, when manufacturing the first optical structure 21 of the present embodiment, a first low refractive index layer 210 having a plurality of concave microstructures can be formed on the first surface 20a of the base layer 20 using a structure wheel. Then, a plurality of concave microstructures are filled with a high refractive index adhesive, and a plurality of concave microstructures are formed on the outer surface of the high refractive index adhesive using the same structure wheel to form a first high refractive index layer 211 covering the first low refractive index layer 210. In this way, in addition to increasing the light beam diffusion effect, the convenience of manufacturing the optical film 2F is also increased.

Therefore, the first high refractive index layer 211 has a plurality of protruding microstructures on the side facing the first low refractive index layer 210, and the shapes of the protruding microstructures and the recessed microstructures match each other. In addition, the light incident surface 211s of the first high refractive index layer 211 also has a plurality of recessed microstructures. It is worth mentioning that each recessed microstructure of the first high refractive index layer 211 and each recessed microstructure of the first low refractive index layer 210 can have substantially the same shape.

In one embodiment, the concave microstructures of the first low refractive index layer 210 and the first high refractive index layer 211 may be the concave microstructure 210A shown in FIG. 16, and the convex microstructure of the first high refractive index layer 211 may be the convex microstructure 211A shown in FIG. 16, but the present invention is not limited thereto. In addition, the position of the concave microstructure of the first high refractive index layer 211 does not necessarily have to be aligned with the concave microstructure of the first low refractive index layer 210. In this way, the light diffusion effect of the optical film 2F can be enhanced.

Similarly, the second optical structure 22 includes a second high refractive index layer 220 and a second low refractive index layer 221. When manufacturing the second optical structure 22 of this embodiment, a second high refractive index layer 220 having a plurality of concave microstructures can be formed on the second surface 20b of the base layer 20 using a structure wheel. Afterwards, the plurality of concave microstructures are filled with a low refractive index adhesive, and the same structure wheel is used to form a plurality of concave microstructures on the outer surface of the low refractive index adhesive, thereby forming a second low refractive index layer 221 covering the second high refractive index layer 220.

Therefore, the second low refractive index layer 221 has a plurality of protruding microstructures on the side facing the second high refractive index layer 220, and the shapes of the protruding microstructures and the recessed microstructures match each other. In addition, the outer surface 221s of the second low refractive index layer 221 has a plurality of recessed microstructures. In addition, the positions of the recessed microstructures of the second low refractive index layer 221 do not necessarily have to be aligned with the recessed microstructures of the second high refractive index layer 220. In this way, the light diffusion effect of the optical film 2F can be improved.

Compared with the embodiment of FIG. 15 , in this embodiment, by making the light incident surface 211s and the light emitting surface (outer surface 221s) of the optical film 2F have multiple concave microstructures, the light diffusion effect of the optical film 2F can be further improved. However, in another embodiment, the second optical structure 22 shown in FIG. 18 can also be omitted, or replaced by the second optical structure 22 shown in FIG. 12 , FIG. 15 or FIG. 17 .

In addition, the optical film 2F and the light-emitting component 1 of the present embodiment are separated from each other to define a gap G1, but the present invention is not limited thereto. In another embodiment not shown in the figure, the optical film 2F of the present embodiment can also be partially connected to the packaging layer 12 of the light-emitting component 1. Since the light-incident surface 211s of the optical film 2F has a plurality of concave microstructures, when the optical film 2F is fixed on the packaging layer 12, a plurality of gaps are defined between the optical film 2F and the packaging layer 12.

[Beneficial effects of the embodiment]

One of the beneficial effects of the present invention is that the optical film and the light-emitting module using the optical film provided by the present invention can diffuse the light beam generated by the light-emitting component 1 through the technical solutions of "optical films 2A-2F, 2B' are arranged on a plurality of light-emitting units 11, and the base layer 20 and the first optical structure 21", "the first optical structure 21 includes a first high refractive index layer 211 and a first low refractive index layer 210, and the first high refractive index layer 211 is located between the light-emitting component 1 and the first low refractive index layer 210", and "the interface between the first high refractive index layer 211 and the first low refractive index layer 210 includes a plurality of first inclined surfaces S1, and each first inclined surface S1 is inclined relative to the thickness direction of the base layer 20", so that the light beam output by the light-emitting module Z1-Z8 has a more uniform brightness distribution.

In addition, by making the first angle θ1 formed by the two connected first inclined surfaces S1, the refractive index n11 of the first high refractive index layer 211, and the refractive index n10 of the first low refractive index layer 210 satisfy the following relationship: θ1≦(180-2*arcsin(n10/n11)), the probability of the light beam generated by the light-emitting unit 11 being totally reflected when it is first projected onto the first inclined surface S1 can be greatly increased, thereby improving the light diffusion effect.

Compared with the existing backlight module, the light-emitting modules Z1-Z8 of the embodiment of the present invention can output diffused point light sources. Accordingly, when the light-emitting modules Z1-Z8 of the embodiment of the present invention are applied to the display device, the diffusion sheet and the brightness enhancement sheet can be omitted. Furthermore, by using the light-emitting modules Z1-Z8 of any embodiment of the present invention in the display device, even if the number of optical films in the optical assembly is reduced, the display area can still have a uniform brightness distribution. In this way, the total thickness of the optical assembly and the size of the display device can be further reduced.

In addition, by using any of the optical films 2A-2F, 2B' provided in the embodiment of the present invention, the light beam generated by the light-emitting component 1 can be diffused. In addition, in the embodiment of the present invention, the interior of the first optical structure 21 (or the second optical structure 22) can have a plurality of bubbles b1 distributed at a high density to increase the refraction, reflection and scattering of the light beam, thereby achieving the effect of diffusing the light beam.

In one embodiment, the first optical structure 21 (or the second optical structure 22) further includes a plurality of nanoparticles P1 distributed therein. Some nanoparticles P1 are combined with some air bubbles b1. Thus, when the first optical structure 21 or the second optical structure 22 is formed, the air bubbles b1 combined with the nanoparticles P1 are more likely to be retained, so that the first optical structure 21 or the second optical structure 22 has more air bubbles b1 to enhance the light diffusion effect.

It should be noted that the optical films 2A-2F, 2B' do not have to be directly arranged on the light-emitting component 1. Other optical films (such as brightness enhancement films) or quantum dot films can also be arranged between the optical films 2A-2F, 2B' and the light-emitting component 1. In addition, the optical films 2A-2F, 2B' of the embodiment of the present invention are not limited to application in the light-emitting modules Z1-Z8, but can also be applied in the optical component and cooperate with other optical films (such as light guide plates) to diffuse the light beam. The optical films 2A-2F, 2B' provided in the embodiment of the present invention can also be applied in lighting devices.

The above disclosed contents are only the preferred feasible embodiments of the present invention, and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the contents of the specification and drawings of the present invention are included in the scope of the patent application of the present invention.

Z1: Light-emitting module

1: Light-emitting components

10: Substrate

100: Base plate

101:Reflective layer

101s: Reflective surfaces

11: Light-emitting unit

12: Packaging layer

2A: Optical film

20: Basal layer

20a: First surface

20b: Second surface

21: First optical structure

210: First low refractive index layer

211: First high refractive index layer

211s: light-entering surface

S1: First slope

Claims (10)

A light-emitting module comprises: a light-emitting component, comprising a substrate and a plurality of light-emitting units arranged on the substrate; and an optical film, which is arranged above the plurality of light-emitting units, wherein the optical film comprises: a base layer; and a first optical structure, which is arranged on the base layer and comprises a first high refractive index layer and a first low refractive index layer, wherein the first high refractive index layer is located between the light-emitting component and the first low refractive index layer, and the interface between the first high refractive index layer and the first low refractive index layer comprises a plurality of first inclined planes, and each of the first inclined planes is inclined relative to the thickness direction of the base layer; wherein two connected first inclined planes jointly form a first angle; wherein the optical film further comprises a second optical structure, and the first optical structure and the second optical structure are connected to each other. The first optical structure is located at two opposite sides of the base layer, the refractive index of the second optical structure is greater than the refractive index of air, the surface of the second optical structure includes a plurality of second inclined planes, and two connected second inclined planes together form a second angle, and the second angle is greater than or equal to the first angle; wherein the first high refractive index layer has a light incident surface facing the light emitting component, and the ratio between the refractive index of the first low refractive index layer and the refractive index of the first high refractive index layer ranges from 0.85 to 0.97; and wherein the first low refractive index layer has a plurality of concave microstructures, and the first high refractive index layer fills the plurality of concave microstructures to form a plurality of protruding microstructures, and the shape of each protruding microstructure matches the shape of the concave microstructure, and each protruding microstructure is a pyramid. The light-emitting module as described in claim 1, wherein at least one of the second optical structure, the first high refractive index layer and the first low refractive index layer has a plurality of bubbles distributed therein. The light-emitting module as described in claim 1, wherein at least one of the first low refractive index layer or the first high refractive index layer contains a plurality of bubbles and a plurality of nanoparticles, and at least one of the nanoparticles is combined with one of the bubbles. A light-emitting module as described in claim 1, wherein each of the concave microstructures is a concave pyramid microstructure, and each of the prisms is a convex pyramid microstructure. The light-emitting module as described in claim 1, wherein the light incident surface has a plurality of recessed microstructures. The light-emitting module as described in claim 5, wherein the first optical structure and the second optical structure are respectively located on the light-incident side and the light-exiting side of the base layer, and the second optical structure includes a second high refractive index layer and a second low refractive index layer, wherein the second high refractive index layer is located between the second low refractive index layer and the light-emitting component, and the second low refractive index layer has an outer surface, and the outer surface has a plurality of concave microstructures. An optical film, comprising: a substrate; and a first optical structure, which is arranged on a light incident side of the substrate and comprises a first high refractive index layer and a first low refractive index layer, wherein the first low refractive index layer is located between the first high refractive index layer and the substrate; wherein the interface formed between the first high refractive index layer and the first low refractive index layer comprises a plurality of first inclined surfaces, and each of the first inclined surfaces is inclined relative to the thickness direction of the substrate, and two connected first inclined surfaces jointly form a first angle; wherein the optical film further comprises a second optical structure, wherein the first optical structure and the second optical structure are respectively located on two opposite sides of the substrate, and the second optical structure is disposed on the substrate. The refractive index of the structure is greater than the refractive index of air, the surface of the second optical structure includes a plurality of second inclined planes, and two connected second inclined planes together form a second angle, and the second angle is greater than or equal to the first angle; wherein the first high refractive index layer has a light incident surface, and the ratio between the refractive index of the first low refractive index layer and the refractive index of the first high refractive index layer ranges from 0.85 to 0.97; and wherein the first low refractive index layer has a plurality of concave microstructures, and the first high refractive index layer fills the plurality of concave microstructures to form a plurality of convex microstructures, and the shape of each convex microstructure matches the shape of the concave microstructure, and each convex microstructure is a pyramid. The optical film as described in claim 7, wherein each of the concave microstructures is a concave pyramid microstructure, each of the prisms is a convex pyramid microstructure, and the convex pyramid microstructure includes at least one triangular slope. The optical film as described in claim 7, wherein the second optical structure includes a second high refractive index layer and a second low refractive index layer, wherein the second high refractive index layer is located between the second low refractive index layer and the base layer, wherein the second high refractive index layer includes a plurality of concave microstructures, and the second low refractive index layer fills the plurality of concave microstructures of the second high refractive index layer to form a plurality of protruding microstructures. The optical film as described in claim 9, wherein the light incident surface has a plurality of concave microstructures, and the second low refractive index layer has an outer surface, and the outer surface has a plurality of concave microstructures.