TW201316043A - Optical film and backlight module using the same - Google Patents

Abstract

An optical film includes a substrate and a plurality of first prism structures is provided. The substrate has a first side and a second side that are opposite to each other. The first prism structures are disposed on the substrate and arranged from the first side toward the second side. Each of the first prism structures has a curved crest. The curved crest has a fluctuation degree. The fluctuation degrees of the first prism structures decrease from the first side toward the second side.

Description

Optical film and backlight module using the same

The present invention relates to an optical film, and more particularly to an optical film applied to a backlight module.

The backlight module is one of the key components of the liquid crystal display. Since the liquid crystal panel itself does not have the ability to emit light, the function of the backlight module is to supply a sufficient light source with uniform brightness and uniform distribution, so that the liquid crystal display can display images normally. At present, liquid crystal displays have been widely used in electronic products with potential for growth such as monitors, notebook computers, digital cameras and projectors, so the demand for backlight modules and related components continues to grow. In general, a liquid crystal display that provides a display screen generally includes a diffusion sheet, a brightness enhancement film (BEF), an upper diffusion sheet, and a light source. At present, most of the trend trends of liquid crystal displays have replaced the conventional cold cathode tube (CCFL) light source with a more energy-saving light-emitting diode (LED) light source.

However, the light-emitting diode is a point light source, and unlike the conventional cold cathode tube as a line light source, the arrangement of the light-emitting diodes spaced apart from each other causes a problem of uneven dispersion of the light source, which also causes the generation of the light-emitting diode. The main cause of the Hot Spot phenomenon. In addition, in order to improve the brightness, the backlight module often places the brightness enhancement film horizontally, but the brightness enhancement film has the effect of image splitting, and thus indirectly causes the hot spot phenomenon to become more serious. Moreover, in the trend of reducing cost and material integration, the backlight module often integrates the upper diffusion sheet and the brightness enhancement film into a composite film, thereby indirectly causing the atomization effect to be deteriorated, and also the problem of the hot spot phenomenon. It is becoming more serious, and the user can easily observe the phenomenon of uneven brightness. Although the liquid crystal display can enlarge the plastic frame in order to shield the hot spot, this method causes the display area to become smaller or the size of the panel module to become larger.

In order to solve the problems of the prior art, a technical aspect of the present invention is an optical film mainly by controlling the film surface haze distribution of the optical film, thereby adjusting the central luminance and the hot spot edge of the optical film. The haze makes the optical film capable of both diffusion and light collecting functions. Therefore, the optical film of the present invention can maintain the brightness of the entire backlight module in the original brightness without affecting the brightness, and at the same time, the hot spot phenomenon of the light-emitting diode can be achieved. Significant atomization effect.

In accordance with an embodiment of the invention, an optical film includes a substrate and a plurality of first tantalum structures. The substrate has two opposing first sides and a second side. The first crucible structure is disposed on the substrate and arranged from the first side toward the second side. Each first tantalum structure has a curved peak. The bending peak has a degree of fluctuation. The degree of fluctuation of the first meandering structure decreases from the first side toward the second side.

In an embodiment of the invention, each of the bending peaks described above has two ends. The end of each bending peak defines a moving average. Each curved peak forms a plurality of waves with respect to a corresponding mean line. The wave of each curved peak has an average wavelength. Each degree of fluctuation decreases as the corresponding average wavelength increases.

In an embodiment of the invention, the center of the substrate has a centerline. The center line is located between the first side and the second side. The average wavelength of the first germanium structure on the first side is generally between 10% and 50% of the average wavelength of the first germanium structure at the midline.

In an embodiment of the invention, the wave of each of the bending peaks has an average amplitude. Each degree of fluctuation increases as the corresponding average amplitude increases.

In an embodiment of the invention, each of the first structures described above has an average vertical height. The average amplitude is less than 20% of the average vertical height.

In an embodiment of the invention, each of the first structures described above has an average horizontal width. The average amplitude is less than 20% of the average horizontal width.

In an embodiment of the invention, the average amplitude of the first meandering structure at the centerline is substantially 10% to 50% of the average amplitude of the first tantalum structure on the first side.

In an embodiment of the invention, the first 稜鏡 structure is located between the first side and the center line.

In an embodiment of the invention, the degree of fluctuation of the first 稜鏡 structure is gradually decreased from the first side and the second side toward the center line.

In an embodiment of the invention, the optical film further includes a plurality of second 稜鏡 structures. The second crucible structure is disposed on the substrate. Each second crucible structure has a flat peak. Each second crucible structure is located between any two adjacent first crucible structures. Moreover, the number of the second meandering structure between any two adjacent first weir structures decreases from the second side toward the first side.

In an embodiment of the invention, the second 稜鏡 structure is located between the second side and the center line.

In an embodiment of the invention, the second 稜鏡 structure is located between any two adjacent first 稜鏡 structures, and is gradually increased from the first side and the second side toward the center line.

In accordance with another embodiment of the present invention, an optical film includes a substrate, a plurality of first tantalum structures, and a plurality of micro-diffusion structures. The substrate has two opposing first sides and a second side. The first crucible structure is disposed on the substrate and arranged from the first side toward the second side. The micro-diffusion structure is disposed on the surface of the first 稜鏡 structure such that each of the first 稜鏡 structures has a degree of light diffusion. The degree of light diffusion of the first meandering structure decreases from the first side toward the second side.

In an embodiment of the invention, the micro-diffusion structure on the first 稜鏡 structure has an average protrusion height. The degree of diffusion of each light decreases as the corresponding average protrusion height decreases.

In an embodiment of the invention, the first 稜鏡 structure has a vertical height. The average protruding height is less than 80% of the vertical height.

In an embodiment of the invention, the average protrusion height of the micro-diffusion structure of the first 稜鏡 structure on the first side is substantially 10 of the average protrusion height of the micro-diffusion structure of the first 稜鏡 structure located at the center line. %~50%.

In an embodiment of the invention, the micro-diffusion structure on each of the first structures has an average density. The average density is the number of micro-diffusion structures contained per unit area. The degree of diffusion of each light decreases as the corresponding average density decreases.

In an embodiment of the invention, the average density of the micro-diffusion structure on the first 稜鏡 structure on the first side is substantially 10 of the average density of the micro-diffusion structure on the first 稜鏡 structure of the center line. %~50%.

In an embodiment of the invention, the light diffusion degree of the first 稜鏡 structure is gradually decreased from the first side and the second side toward the center line.

In an embodiment of the invention, the optical film further includes a plurality of second 稜鏡 structures. The second crucible structure is disposed on the substrate. Each second crucible structure has a smooth surface. Each second crucible structure is located between any two adjacent first crucible structures. Moreover, the number of the second meandering structure between any two adjacent first weir structures decreases from the second side toward the first side.

In an embodiment of the invention, the micro-diffusion structure is spherical or polygonal.

Another technical aspect of the present invention is a backlight module, which is mainly achieved by the conventional method of using the present invention to simultaneously have an optical film with diffusion and light collecting functions, thereby saving the traditional method of adding an additional diffusion sheet. The purpose of reducing costs. In other words, the backlight module of the present invention does not need to use the upper diffusion sheet, so the backlight module adopting the traditional multilayer optical film structure can reduce the number of stacked optical films, in addition to avoiding the scraping between the optical films. The problem of scratching can also reduce the assembly time of the optical film and the overall thickness of the backlight module.

According to another embodiment of the present invention, a backlight module includes a light guide plate, a plurality of first light emitting diodes, a diffusion sheet, and an optical film. The light guide plate has a first light incident surface and a light exit surface. The first light incident surface is connected to the light exit surface. The first light emitting diodes are arranged along the first light incident surface. The diffusion sheet is disposed on the light emitting surface. The optical film comprises a substrate and a plurality of first tantalum structures. The substrate is disposed on the diffusion sheet. The first germanium structure is disposed on the substrate and extends along the direction in which the first light emitting diodes are arranged. The first 稜鏡 structure adjacent to the region of the light-emitting diode will diffuse more than the region away from the light-emitting diode

In an embodiment of the invention, one of the first raft structures has a curved apex to form a different degree of diffusion.

In an embodiment of the invention, one of the first germanium structures has a plurality of micro-diffusion structures to form different degrees of diffusion.

The embodiments of the present invention are disclosed in the following drawings, and for the purpose of illustration However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not necessary. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic representation.

One aspect of the present invention is a backlight module. More specifically, it mainly uses the optical film which can simultaneously diffuse and collect light function by using the invention, thereby saving the traditional practice of adding an additional diffusion sheet to achieve the purpose of reducing cost. In other words, the backlight module of the present invention does not need to use the upper diffusion sheet, so the backlight module adopting the traditional multilayer optical film structure can reduce the number of stacked optical films, in addition to avoiding the scraping between the optical films. The problem of scratching can also reduce the assembly time of the optical film and the overall thickness of the backlight module.

Please refer to Figure 1. FIG. 1 is a side view showing a backlight module 1 according to an embodiment of the invention.

As shown in FIG. 1 , in the present embodiment, the backlight module 1 includes a light guide plate 10 , a plurality of first light emitting diodes 12 , a diffusion sheet 14 , and an optical film 16 a . The light guide plate 10 of the backlight module 1 has a first light incident surface 100a and a light exit surface 100b. The first light incident surface 100a of the light guide plate 10 is connected to the light exit surface 100b. The first light-emitting diodes 12 of the backlight module 1 are horizontally arranged along the first light-incident surface 100a of the light guide plate 10. Since the first drawing is a side view of the backlight module 1 of the present invention, only one first light emitting diode 12 is shown. The diffusion sheet 14 of the backlight module 1 is disposed on the light-emitting surface 100b of the light guide plate 10. The optical film 16a of the backlight module 1 is disposed on the diffusion sheet 14. In other words, the diffusion sheet 14 and the optical film 16a of the backlight module 1 are stacked on the light-emitting surface 100b of the light guide plate 10 from bottom to top. In addition, a reflective pattern 102 is further disposed on the bottom of the light guide plate 10 of the backlight module 1 . Therefore, after the light emitted by the first light-emitting diode 12 of the backlight module 1 enters the light guide plate 10 through the first light-incident surface 100a, the light is then reflected by the light-reflecting pattern 102 at the bottom of the light guide plate 10. The light-emitting surface 100b leaves the light guide plate 10, and sequentially exits the backlight module 1 through the diffusion sheet 14 and the optical film 16a.

Please refer to Figure 2. Fig. 2 is a perspective view showing the optical film 16a in Fig. 1.

As shown in FIG. 2, in the present embodiment, the optical film 16a of the backlight module 1 includes a substrate 160 and a plurality of first dam structures 162. The substrate 160 of the optical film 16a is disposed on the diffusion sheet 14 of the backlight module 1 and has two opposite first sides 160a and second sides 160b. The first side 160a of the substrate 160 is on the same side as the first light incident surface 100a of the light guide plate 10 and adjacent to the first light emitting diode 12. The first meandering structure 162 of the optical film 16a is disposed on the substrate 160. The first meandering structure 162 of the optical film 16a extends along the direction in which the first light emitting diodes 12 are arranged and is aligned from the first side 160a of the substrate 160 toward the second side 160b. The degree of diffusion of the first germanium structure 162 adjacent to the region of the light emitting diode 12 may be greater than the extent of diffusion of the first germanium structure 162 away from the region of the light emitting diode 12. In this embodiment, each first 稜鏡 structure 162 has a curved peak 162a. In this embodiment, each first 稜鏡 structure 162 has a curved top angle line, and the top corner line forms a curved peak 162a. In other words, the curved peak 162a is a curve having a different curvature, and is not meant to be a specific peak and trough position of a dot.

The bending peak 162a of the first meandering structure 162 has a degree of fluctuation. The means for adjusting the degree of diffusion of the first meandering structure 162 in this embodiment can be achieved by varying the degree of fluctuation of the curved peak 162a. The degree of fluctuation of the first meandering structure 162 is gradually decreased from the first light incident surface 100a adjacent to the light guide plate 10 away from the first light incident surface 100a, that is, the degree of fluctuation of the first tantalum structure 162 adjacent to the light emitting diode 12 Greater than other areas.

Please refer to FIG. 3A, FIG. 3B and FIG. 3C. FIG. 3A is a top view showing one of the first dam structures 162 of the optical film 16a of FIG. 2. FIG. 3B is a perspective view showing the first 稜鏡 structure 162 in FIG. 3A, wherein the first 稜鏡 structure 162 is in the form of left and right yaw. 3C is a perspective view showing another embodiment of the first meandering structure 162 of FIG. 3A, wherein the first meandering structure 162 is in the form of ups and downs.

As shown in FIG. 3A and FIG. 3B, in the present embodiment, the bending peaks 162a of each of the first meandering structures 162 have both end points P. A line connecting the two end points P of each of the bending peaks 162a may be defined as a moving average L. The curved peaks 162a of each of the first meandering structures 162 may form a plurality of waves with respect to the respective moving averages L.

In one aspect, each of the plurality of waves formed by each of the bending peaks 162a has a specific wavelength W, and after a plurality of specific wavelengths W of the same bending peak 162a are averaged, the bending peak 162a is obtained. The average wavelength Wm. In other words, the average wavelength Wm can be obtained by averaging the wavelengths of all the waves on the curved peak 162a. The degree of fluctuation of each first meandering structure 162 decreases as the respective average wavelength Wm increases. (Note: Figure 3A is a top view of a single first tantalum structure 162, not three curved peaks). In other words, if the wave of the curved peak 162a has a shorter average wavelength Wm, except for the number of waves representing the curved peak 162a. More, it also means that the first meandering structure 162 has a curved swinging direction with a relatively high frequency. Since the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, a hot spot phenomenon caused by the first light-emitting diode 12 may occur in the first light incident adjacent to the light guide plate 10. Face 100a. By having the first meandering structure 162 of the first light incident surface 100a closest to the light guide plate 10 (i.e., the first side 160a of the substrate 160) having the shortest average wavelength Wm, and making the first meandering structure 162 The average wavelength Wm is gradually increased from the first light incident surface 100a adjacent to the light guide plate 10 away from the first light incident surface 100a (that is, the second side 160b of the substrate 160), except that the first light emitting diode 12 can be effectively applied. The resulting hot spot phenomenon produces an atomization effect that is not conspicuous, and allows the light emitted from the optical film 16a to have a continuous taste (i.e., luminance and chromaticity). In other words, the use of the first meandering structure 162 having a higher degree of fluctuation can atomize the hot spot phenomenon close to the side of the first smooth surface 100a while transmitting the first meandering structure 162 having the degree of fluctuation of the gradient, thereby making the whole The light exit surface 100b has continuous luminance and chromaticity changes.

On the other hand, each of the plurality of waves formed by each of the bending peaks 162a has a specific amplitude A, and the average amplitude A of the same bending peak 162a is averaged to be a curved peak. The average amplitude Am of 162a. In other words, the average amplitude Am can be obtained by averaging the amplitudes of all the waves on the curved peak 162a. The degree of fluctuation of each of the first meandering structures 162 increases as the respective average amplitude Am increases. In other words, if the wave of the bending peak 162a has a large average amplitude Am, except that the entire length of the bending peak 162a is longer, it also means that the first 稜鏡 structure 162 has a undulating curved oscillating course. By having the first meandering structure 162 of the first light incident surface 100a closest to the light guide plate 10 have the largest average amplitude Am, and the average amplitude Am of the first meandering structure 162 is made first by the adjacent light guide plate 10 The smooth surface 100a is gradually decreased away from the first light incident surface 100a, and the light emitting effect of the optical film 16a can be made even more obvious, except that the atomization effect of the hot spot phenomenon caused by the first light emitting diode 12 can be effectively made. Has a continuous taste.

As shown in FIGS. 3A and 3B, each of the first meander structures 162 of the optical film 16a may have an average vertical height V1m and an average horizontal width Hm. Further, if the first 稜鏡 structure 162 of the optical film 16a is in the form of left and right yaw, the first 稜鏡 structure 162 has a plurality of triangular sections of unequal width, and the same first 稜鏡 structure 162 is triangular. The horizontal width H of the cross section is averaged to be the average horizontal width Hm of the first tantalum structure 162. In other words, the average horizontal width Hm is the average of the horizontal width of the first tantalum structure 162 relative to the substrate 160.

As shown in FIG. 3C, if the first 稜鏡 structure 162 of the optical film 16a is in the form of ups and downs, the first 稜鏡 structure 162 has a plurality of triangular sections of unequal height, and the same first 稜鏡 structure The vertical height V1 of each of the triangular cross sections 162 is averaged, and is the average vertical height V1m of the first meandering structure 162. In other words, the average vertical height V1m is the average of the vertical heights of the first tantalum structure 162 relative to the substrate 160.

In this embodiment, in order to prevent the first 稜鏡 structure 162 on the optical film 16a from being excessively fluctuated, the light emitted from the optical film 16a is not good, and the brightness is lowered, and each first 稜鏡The average amplitude Am of the structure 162 may be less than 20% of the average vertical height V1m or 20% of the average horizontal width Hm, thereby simultaneously achieving the effect of atomization on the hot spot and allowing the light emitted from the optical film 16a to have a better taste. In this embodiment, the first 稜鏡 structure 162 of the optical film 16a is not limited to only up and down (as shown in FIGS. 3A and 3B) or left and right offset (as shown in FIG. 3C). Can swing up and down arbitrarily. In the different embodiments described above, the first meandering structure 162 can have ups and downs, swings left and right to cause different degrees of fluctuation, in other words, by changing the specific wavelength W of the curved peak 162a of the first meandering structure 162 ( Or average wavelength Wm), specific amplitude A (or average amplitude Am), vertical height V (or average vertical height Vm), or horizontal width H (or average horizontal width Hm) such that the first meandering structure 162 has a top with different curvature The corners are formed to form different degrees of fluctuation to change the degree of diffusion of the first meandering structure 162.

Please refer to Figure 4A. Fig. 4A is a top view showing the optical film 16a in Fig. 2.

As shown in FIG. 4A, the center of the substrate 160 of the optical film 16a has a center line C, and the center line C of the substrate 160 is located between the first side 160a and the second side 160b. In the present embodiment, the center line C is located between the first side 160a and the second side 160b, and the base 160 is equally divided into two. The average wavelength Wm of the first germanium structure 162 on the first side 160a of the substrate 160 is substantially 10% to 50% of the average wavelength Wm of the first germanium structure 162 located in the center line C of the substrate 160, that is, at the first The average wavelength Wm of the first germanium structure 162 of one side 160a will be greater than the average wavelength Wm of the first germanium structure 162 located at the centerline C. In this embodiment, only the center line C located between the first side 160a and the second side 160b is used as the boundary line, but it is not limited thereto, and the position of the boundary line can be adjusted according to requirements. For example, the centerline C can be located at the center of the viewable area, where the viewable area is the area of the display panel that has a display effect. In this embodiment, since the degree of fluctuation of the first meandering structure 162 is gradually reduced by the gradient of the first light incident surface 100a adjacent to the light guide plate 10 away from the first light incident surface 100a, the user is observing the optical film. When the light is emitted from the sheet 16a, the light is perceived to have a smoother taste.

On the other hand, in order to make the degree of fluctuation of the first meandering structure 162 from the first light incident surface 100a adjacent to the light guide plate 10 to the distance from the first light incident surface 100a, the gradient is moderated, and the user is observed by When the light emitted by the optical film 16a is light, the light has a smoother taste. In an embodiment, the average amplitude Am of the first ridge structure 162 on the first side 160a of the substrate 160 can be substantially at the base. The first amplitude structure 162 of the 160 center line C has an average amplitude Am of 10% to 50%.

Please refer to Figure 4B. Figure 4B is a top plan view showing another embodiment of the optical film 16a of Figure 4A.

As shown in FIG. 4B, in the present embodiment, if the degree of fluctuation of the first meandering structure 162 is gradually decreased from the first light incident surface 100a adjacent to the light guide plate 10 toward the first light incident surface 100a, the optical film is removed. When the taste effect of the light emitted by 16b is not significant, the first meandering structure 162 of the optical film 16b may also be concentrated between the first side 160a of the substrate 160 and the centerline C. Thereby, the optical film 16b having a smaller number of the first meandering structures 162 has an advantage of being easy to process in manufacturing, and the manufacturing yield of the optical film 16b can also be improved.

As shown in FIGS. 4A and 4B, the optical film 16a and the optical film 16b include a plurality of second dam structures 164 in addition to the substrate 160 and the first 稜鏡 structure 162. The second meandering structure 164 is disposed on the substrate 160. Each second meandering structure 164 has a flat peak 164a. Since the flat peak 164a of the second germanium structure 164 does not have the function of atomizing the hot spot phenomenon caused by the first light emitting diode 12, the second germanium structure 164 can be separated from the first light emitting diode 12 by the substrate 160. The second side 160b is aligned toward the first side 160a adjacent to the first light emitting diode 12. In this embodiment, the flat peaks 164a of each of the second turns 164 are parallel to the first side 160a and the second side 160b of the substrate 160, but are not limited thereto. In another embodiment, the flat peaks 164a of each of the second turns 164 may also be parallel to one another but not parallel to the first side 160a and the second side 160b of the substrate 160.

Please refer to Figure 4C. Figure 4C is a top plan view showing another embodiment of the optical film 16a of Figure 4A.

As shown in FIG. 4C, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 162, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 162 is gradually reduced by the second side 160b of the substrate 160 toward the first side 160a. The optical film 16c of the present embodiment is formed by increasing the number between any two adjacent first 稜鏡 structures 162 from the first side 160a of the substrate 160 toward the second side 160b. The light emitted from the sheet 16c has a smoother taste, and the visual effect that can be achieved is similar to the degree of fluctuation of the first meandering structure 162 from the first light incident surface 100a of the adjacent light guiding plate 10 away from the first light entering. The face 100a is gradually reduced.

Please refer to Figure 5. FIG. 5 is a side view showing a backlight module 3 according to another embodiment of the present invention.

As shown in FIG. 5, in the present embodiment, the backlight module 3 includes a plurality of light guide plates 10, a plurality of first light-emitting diodes 12, a diffusion sheet 14, and an optical film 16d. Two light emitting diodes 18. In addition, the light guide plate 10 of the backlight module 3 includes a second light incident surface 100c in addition to the first light incident surface 100a and the light exit surface 100b. The first light incident surface 100a and the second light incident surface 100c of the light guide plate 10 are connected to the light exit surface 100b, respectively. The first light emitting diodes 12 of the backlight module 3 are horizontally arranged along the first light incident surface 100a of the light guide plate 10, and the second light emitting diodes 18 are horizontally along the second light incident surface 100c of the light guide plate 10. arrangement. Since FIG. 5 is a side view of the backlight module 3 of the present invention, only one first light emitting diode 12 and one second light emitting diode 18 are shown. Therefore, after the light emitted by the first light-emitting diode 12 and the second light-emitting diode 18 of the backlight module 3 passes through the first light-incident surface 100a and the second light-incident surface 100c, respectively, after entering the light guide plate 10, The light is then reflected by the reflective pattern 102 located at the bottom of the light guide plate 10, exits the light guide plate 10 through the light exit surface 100b, and sequentially exits the backlight module 3 through the diffusion sheet 14 and the optical film 16d.

Please refer to Figure 6A. Fig. 6A is a top view showing the optical film 16d in Fig. 5.

As shown in FIG. 6A, in the embodiment, the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, and the second light-emitting diode 18 faces the second light-guide plate 10. The light incident surface 100c, so the hot spot phenomenon caused by the first light emitting diode 12 and the second light emitting diode 18 respectively occurs adjacent to the first light incident surface 100a and the second light incident surface 100c of the light guide plate 10 . By first rib of the first light incident surface 100a (i.e., the first side 160a of the substrate 160) and the second light incident surface 100c (i.e., the second side 160b of the substrate 160) of the light guide plate 10 The mirror structure 162 has the greatest degree of fluctuation (the first meandering structure 162 can have the shortest average wavelength Wm or the maximum average amplitude Am), and the degree of fluctuation of the first meandering structure 162 is respectively caused by the first entrance adjacent to the light guide plate 10. The smooth surface 100a and the second light incident surface 100c are gradually increased toward the center line C of the substrate 160, except that the atomization effect of the hot spot phenomenon caused by the first light emitting diode 12 and the second light emitting diode 18 can be effectively generated. Not obvious, the light emitted from the optical film 16d can be made to have a continuous taste.

Please refer to Figure 6B. Fig. 6B is a top view showing another embodiment of the optical film 16d in Fig. 6A.

As shown in FIG. 6B, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 162, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 162 is increased from the first side 160a and the second side 160b of the substrate 160 toward the centerline C, respectively. The optical film 16e of the present embodiment is formed by increasing the number between any two adjacent first 稜鏡 structures 162 from the first side 160a and the second side 160b of the substrate 160 toward the center line C, respectively. As a means for making the light emitted from the optical film 16e have a smoother taste, the visual effect that can be achieved is similar to the degree of fluctuation of the first meandering structure 162 by the first light incident surface 100a adjacent to the light guide plate 10, respectively. The method of decreasing with the second light incident surface 100c toward the center line C of the substrate 160.

Please refer to Figure 7 and Figure 8A. Figure 7 is a side elevational view of another embodiment of one of the first raft structures 162 of the optical film 16a of Figure 1. Fig. 8A is a top view showing an embodiment of the optical film 16a of Fig. 2, which uses the first 稜鏡 structure 362 of Fig. 7.

As shown in Fig. 7 and Fig. 8A, this embodiment is modified for the optical film 16a of Fig. 1, particularly for the first 稜鏡 structure 162 of the optical film 16a. In the present embodiment, the optical film 36a also includes a substrate 160. The first meandering structure 362 of the optical film 36a extends along the direction in which the first light emitting diodes 12 are arranged, and is aligned by the first side 160a of the substrate 160 toward the second side 160b. The degree of diffusion of the first germanium structure 362 adjacent to the region of the light emitting diode 12 may be greater than the extent of diffusion of the first germanium structure 362 away from the region of the light emitting diode 12. In the present embodiment, the optical film 36a includes a plurality of micro-diffusion structures 362a. The micro-diffusion structure 362a of the optical film 36a is disposed on the surface of the first dam structure 362 such that each of the first 稜鏡 structures 362 has a degree of light diffusion. The means for adjusting the degree of diffusion of the first meandering structure 362 in this embodiment can be achieved by changing the degree of light diffusion of the first meandering structure 362. The degree of light diffusion of the first meandering structure 362 is gradually reduced from the first side 160a toward the second side 160b (i.e., decreasing from the first light incident surface 100a adjacent to the light guide plate 10 away from the first light incident surface 100a).

As shown in Fig. 7, in the present embodiment, each micro-diffusion structure 362a has a protrusion height S. The protrusion height S can be defined as the vertical height of each micro-diffusion structure 362a that is furthest from the surface of the first raft structure 362. In the plurality of micro-diffusion structures 362a formed by the first raft structure 362, each of the micro-diffusion structures 362a has a specific protrusion height S, and a specific protrusion of the plurality of micro-diffusion structures 362a on the same first 稜鏡 structure 362 After the height S is averaged, it is the average protruding height Sm of the micro-diffusion structure 362a on the first 稜鏡 structure 362. In other words, the degree of light diffusion of each of the first raft structures 362 decreases as the average protrusion height Sm of the respective micro-diffusion structures 362a decreases. In other words, if the micro-diffusion structure 362a on the first 稜鏡 structure 362 has a large average protrusion height Sm, in addition to representing a large size of the micro-diffusion structure 362a, it also represents that the first 稜鏡 structure 362 has a large light diffusion capability. . Since the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, a hot spot phenomenon caused by the first light-emitting diode 12 may occur adjacent to the first light-incident surface 100a of the light guide plate 10. . By having the micro-diffusion structure 362a on the first meandering structure 362 of the first light-incident surface 100a closest to the light guide plate 10 (that is, the first side 160a of the substrate 160) has the largest average protruding height Sm, and The average protruding height Sm of the micro-diffusion structure 362a is gradually decreased from the first light-incident surface 100a adjacent to the light guide plate 10 away from the first light-incident surface 100a (that is, the second side 160b of the substrate 160), except that the first light-emitting surface 362a can be effectively The hot spot phenomenon caused by the light-emitting diode 12 produces an atomization effect which is not obvious, and the light emitted from the optical film 36a has a continuous taste.

Also shown in Fig. 7, in the present embodiment, the first meandering structure 362 has a vertical height V2. In order to avoid the poor taste of the light emitted from the optical film 36a due to the excessive diffusion of the first 稜鏡 structure 362, the average protrusion height Sm of each micro-diffusion structure 362a is preferably smaller than the vertical height of the first 稜鏡 structure 362. 80% of V2, at the same time, achieves the effect of atomization on the hot spot, and makes the light emitted from the optical film 36a have a better taste.

Also shown in FIG. 8A, in the present embodiment, the average protrusion height Sm of the micro-diffusion structure 362a on the first 稜鏡 structure 362 of the first side 160a of the substrate 160 is substantially at the center line C of the substrate 160. 10% to 50% of the average protrusion height Sm of the micro-diffusion structure 362a of the structure 362, that is, the average protrusion height Sm of the micro-diffusion structure 362a located on the first side 160a (the first light-incident surface 100a) is larger than the center line The micro-diffusion structure 362a of C. Since the degree of light diffusion of the micro-diffusion structure 362a is gradually reduced by the gradient of the first light-incident surface 100a adjacent to the light-guiding plate 10 away from the first light-incident surface 100a, when the user observes the light emitted by the optical film 36a, It will feel light with a smoother taste. In addition, for convenience of explanation, the present specification explains the relationship between the average protruding height Sm and the distribution only by the micro-diffusion structure 362a having the same particle diameter in the same 稜鏡 structure, but the present invention is not limited thereto, and the same first 稜鏡 structure The micro-diffusion structure 362a of different particle sizes may be formed in 362 to form an average protrusion height Sm.

Please refer to Figure 8B. Figure 8B is a top plan view showing another embodiment of the optical film 36a of Figure 8A.

As shown in FIG. 8B, in the present embodiment, if the light diffusion degree of the first meandering structure 362 is gradually decreased from the first light incident surface 100a adjacent to the light guide plate 10 toward the first light incident surface 100a, the optical film is removed. When the taste effect of the light emitted from the sheet 36b is not significant, the first meandering structure 362 of the optical film 36b may also be concentrated between the first side 160a of the substrate 160 and the center line C. In other words, the average protrusion height Sm of the micro-diffusion structure 362a on the first side 160a (the first light-incident surface 100a) is larger than the micro-diffusion structure 362a located on the center line C, and the structure of the center line C may have no micro-diffusion. Structure 362a. Thereby, the optical film 36b having a smaller number of the first meandering structures 362 has an advantage of being easy to process in manufacturing, and the manufacturing yield of the optical film 36b can also be improved.

As shown in FIGS. 8A and 8B, the optical film 36a and the optical film 36b also include a plurality of second dam structures 164 in addition to the substrate 160 and the first 稜鏡 structure 362. The second meandering structure 164 is disposed on the substrate 160. Each of the second turns 164 has a smooth surface. In other words, the second tantalum structure 164 does not have micro-diffused particles or other microstructures that can have an atomizing function. Since the smooth surface of the second germanium structure 164 does not have the function of atomizing the hot spot phenomenon caused by the first light emitting diode 12, the second germanium structure 164 can be separated from the first light emitting diode 12 by the substrate 160. The two sides 160b are arranged toward the first side 160a adjacent to the first light emitting diode 12.

Please refer to Figure 8C. Figure 8C is a top plan view showing another embodiment of the optical film 36a of Figure 8A.

As shown in FIG. 8C, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 362, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 362 is gradually reduced by the second side 160b of the substrate 160 toward the first side 160a. In this embodiment, the average protruding height Sm of the 稜鏡 structure adjacent to the region of the first light incident surface 100a is greater than other regions or the center line C, and the average protruding height Sm can be interpreted as a plurality of first 稜鏡 structures 362 (ie, Formed in the region, the non-single first meandering structure 362, that is, the average protruding height Sm decreases as the respective regions are further away from the first light incident surface 100a. The optical film 36c of the present embodiment is formed by increasing the number between any two adjacent first 稜鏡 structures 362 from the first side 160a of the substrate 160 toward the second side 160b. The light emitted by the sheet 36c has a smoother taste, and the visual effect that can be achieved is similar to that the light diffusion degree of the first 稜鏡 structure 362 is away from the first light incident surface 100a of the adjacent light guide plate 10 away from the first entrance. The smoothing of the smooth surface 100a.

Please refer to Figure 8D. Figure 8D is a top plan view showing another embodiment of the optical film 36a of Figure 8A.

As shown in FIG. 8D, the optical film 36d of the present embodiment is suitably applied to the backlight module 3 including the first light-emitting diode 12 and the second light-emitting diode 18 in FIG. Since the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, and the second light-emitting diode 18 faces the second light-incident surface 100c of the light guide plate 10, the first light-emitting diode 12 The phenomenon of hot spots caused by the second light-emitting diodes 18 respectively occurs adjacent to the first light-incident surface 100a and the second light-incident surface 100c of the light guide plate 10. By first rib of the first light incident surface 100a (i.e., the first side 160a of the substrate 160) and the second light incident surface 100c (i.e., the second side 160b of the substrate 160) of the light guide plate 10 The mirror structure 362 has the greatest degree of light diffusion (the micro-diffusion structure 362a has a maximum average protrusion height Sm), and the light diffusion degree of the first 稜鏡 structure 362 is respectively caused by the first light-incident surface 100a adjacent to the light guide plate 10 and the first The diffractive surface 100c is gradually reduced toward the center line C of the substrate 160, except that the atomization effect of the hot spot phenomenon caused by the first LED 12 and the second LED 18 is effectively not obvious, and The light emitted from the optical film 36d has a continuous taste.

Please refer to Figure 8E. Figure 8E is a top plan view showing another embodiment of the optical film 36a of Figure 8A.

As shown in FIG. 8E, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 362, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 362 is increased from the first side 160a and the second side 160b of the substrate 160 toward the centerline C, respectively. The optical film 36e of the present embodiment is gradually increased from the first side 160a and the second side 160b of the substrate 160 toward the center line C by the number between the two adjacent first 稜鏡 structures 362, respectively. As a means for imparting a smoother taste to the light emitted from the optical film 36e, the visual effect that can be achieved is similar to that of the first enamel structure 362 being diffused by the first light incident surface of the adjacent light guide plate 10, respectively. The approach of 100a and the second light incident surface 100c toward the center line C of the substrate 160 is gradually reduced.

Please refer to Figure 9A. Fig. 9A is a top view showing another embodiment of the optical film 36a in Fig. 8A.

As shown in FIG. 9A, in the present embodiment, a micro-diffusion structure 562a of the same particle size is used on each first 稜鏡 structure 562, and the micro-diffusion structure 562a on each first 稜鏡 structure 562 has an average density. . The average density can be defined as the number of micro-diffusion structures 562a included on a unit area. The degree of light diffusion of each first germanium structure 562 decreases as the average density of the respective microdiffused structures 562a decreases. In other words, if the micro-diffusion structure 562a on the first germanium structure 562 has a large average density, that is, the first germanium structure 562 has a large light diffusing capability. Since the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, a hot spot phenomenon caused by the first light-emitting diode 12 may occur adjacent to the first light-incident surface 100a of the light guide plate 10. . The micro-diffusion structure 562a on the first 稜鏡 structure 562 of the first light-incident surface 100a closest to the light guide plate 10 (that is, the first side 160a of the substrate 160) has the largest average density and micro-diffusion The average density of the structure 562a is gradually reduced from the first light incident surface 100a adjacent to the light guide plate 10 away from the first light incident surface 100a (that is, the second side 160b of the substrate 160), except that the first light emitting diode can be effectively applied. The hot spot phenomenon caused by 12 produces an atomization effect which is not obvious, and the light emitted from the optical film 56a has a continuous taste.

Also shown in FIG. 9A, in the present embodiment, the average density of the micro-diffusion structure 562a on the first ridge structure 562 of the first side 160a of the substrate 160 is substantially the first ridge of the line C in the base 160. The micro-diffusion structure 562a of the mirror structure 562 has an average density of 10% to 50%, that is, the average density of the micro-diffusion structure 562a located in the first side 160a region is greater than the micro-diffusion structure 562a located in the mid-line C region. Since the degree of light diffusion of the micro-diffusion structure 562a is gradually reduced by the gradient of the first light-incident surface 100a adjacent to the light-guiding plate 10 away from the first light-incident surface 100a, when the user observes the light emitted by the optical film 56a, It will feel light with a smoother taste.

Please refer to Figure 9B. Fig. 9B is a top view showing another embodiment of the optical film 56a in Fig. 9A.

As shown in FIG. 9B, in the present embodiment, if the light diffusion degree of the first meandering structure 562 is gradually decreased from the first light incident surface 100a adjacent to the light guide plate 10 toward the first light incident surface 100a, the optical film is removed. When the taste effect of the light emitted from the sheet 56b is not significant, the first meandering structure 562 of the optical film 56b may also be concentrated between the first side 160a of the substrate 160 and the center line C. Thereby, the optical film 56b having a smaller number of the first meandering structures 562 has an advantage of being easy to process in manufacturing, and the manufacturing yield of the optical film 56b can also be improved.

As shown in FIGS. 9A and 9B, the optical film 56a and the optical film 56b also include a plurality of second 稜鏡 structures 164 in addition to the substrate 160 and the first 稜鏡 structure 562. The second meandering structure 164 is disposed on the substrate 160. Each of the second turns 164 has a smooth surface. Since the smooth surface of the second germanium structure 164 does not have the function of atomizing the hot spot phenomenon caused by the first light emitting diode 12, the second germanium structure 164 can be separated from the first light emitting diode 12 by the substrate 160. The two sides 160b are arranged toward the first side 160a adjacent to the first light emitting diode 12.

Please refer to Figure 9C. Figure 9C is a top plan view showing another embodiment of the optical film 56a of Figure 9A.

As shown in FIG. 9C, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 562, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 562 is gradually reduced from the second side 160b of the substrate 160 toward the first side 160a. In this embodiment, the average density of the first 稜鏡 structure 562 near the first light-incident surface 100a is greater than other regions or the center line C, and the average density can be interpreted as a plurality of first 稜鏡 structures 562 (ie, regions). The inner first 稜鏡 structure 562 is formed, that is, the average density decreases as the respective regions are further away from the first light incident surface 100a. The optical film 56c of the present embodiment is formed by increasing the number between any two adjacent first 稜鏡 structures 562 from the first side 160a of the substrate 160 toward the second side 160b. The light emitted from the sheet 56c has a smoother taste, and the visual effect that can be achieved is similar to that the light diffusion degree of the first 稜鏡 structure 562 is away from the first light incident surface 100a of the adjacent light guide plate 10 away from the first entrance. The smoothing of the smooth surface 100a.

Please refer to Figure 9D. Fig. 9D is a top view showing another embodiment of the optical film 56a in Fig. 9A.

As shown in FIG. 9D, the optical film 56d of the present embodiment is suitably applied to the backlight module 3 including the first light-emitting diode 12 and the second light-emitting diode 18 in FIG. Since the first light-emitting diode 12 faces the first light-incident surface 100a of the light guide plate 10, and the second light-emitting diode 18 faces the second light-incident surface 100c of the light guide plate 10, the first light-emitting diode 12 The phenomenon of hot spots caused by the second light-emitting diodes 18 respectively occurs adjacent to the first light-incident surface 100a and the second light-incident surface 100c of the light guide plate 10. By first rib of the first light incident surface 100a (i.e., the first side 160a of the substrate 160) and the second light incident surface 100c (i.e., the second side 160b of the substrate 160) of the light guide plate 10 The mirror structure 562 has the greatest degree of light diffusion (the micro-diffusion structure 562a has the largest average density), and the light diffusion degree of the first 稜鏡 structure 562 is respectively from the first light-incident surface 100a adjacent to the light guide plate 10 and the second entrance. The smooth surface 100c is gradually decreased toward the center line C of the substrate 160, except that the atomization effect of the hot spot phenomenon caused by the first light-emitting diode 12 and the second light-emitting diode 18 can be effectively made, which is not obvious, and can be made optical. The light emitted from the diaphragm 56d has a continuous taste.

Please refer to Figure 9E. Fig. 9E is a top view showing another embodiment of the optical film 56a in Fig. 9A.

As shown in FIG. 9E, in the present embodiment, each second 稜鏡 structure 164 is located between any two adjacent first 稜鏡 structures 562, and the second 稜鏡 structure 164 is located at any two adjacent The number of turns between the structures 562 is increased from the first side 160a and the second side 160b of the substrate 160 toward the centerline C, respectively. The optical film 56e of the present embodiment is gradually increased from the first side 160a and the second side 160b of the substrate 160 toward the center line C by the number between the two adjacent first 稜鏡 structures 562, respectively. As a means for making the light emitted from the optical film 56e have a smoother taste, the visual effect that can be achieved is similar to that the first light-emitting surface of the first meandering structure 562 is diffused from the first light-incident surface of the adjacent light guiding plate 10, respectively. The approach of 100a and the second light incident surface 100c toward the center line C of the substrate 160 is gradually reduced.

In one embodiment, the micro-diffusion structures 362a, 562a on the first raft structures 362, 562 may be spherical or polygonal, but are not limited thereto.

In one embodiment, in order to manufacture the micro-diffusion structures 362a, 562a on the first 稜鏡 structures 362, 562 in FIGS. 7 to 9E, respectively, the manufacturing tool-machining wheel of the optical films 36a-56e The sandblasting process is performed on the surface, and a circular sand material or a polygonal sand material may be used according to the shape of the required micro-diffusion structures 362a and 562a, whereby the micro-diffusion structure 362a is formed on the substrate 160 after the transfer, The first structure 362, 562 of 562a. Alternatively, a laser engraving process may be performed on the surface of the processing wheel, and the first crucible structures 362, 562 having the micro-diffusion structures 362a, 562a may be separately formed on the substrate 160 after the transfer.

From the above detailed description of specific embodiments of the present invention, it can be clearly seen that the optical film of the present invention mainly adjusts the central luminance of the optical film by controlling the film surface haze distribution of the optical film. The haze of the hot spot allows the optical film to simultaneously function as both diffusion and light collecting. Therefore, the optical film of the present invention can maintain the brightness of the entire backlight module in the original brightness without affecting the brightness, and at the same time, the hot spot phenomenon of the light-emitting diode can be achieved. Significant atomization effect. In addition, the backlight module of the present invention mainly adopts the optical film which can simultaneously have the diffusion and the light collecting function by using the invention, thereby saving the traditional practice of adding an additional diffusion sheet to achieve the purpose of reducing the cost. In other words, the backlight module of the present invention does not need to use the upper diffusion sheet, so the backlight module adopting the traditional multilayer optical film structure can reduce the number of stacked optical films, in addition to avoiding the scraping between the optical films. The problem of scratching can also reduce the assembly time of the optical film and the overall thickness of the backlight module.

While the present invention has been described above by way of example only, it is not intended to limit the invention, and the invention may be modified and modified in various ways without departing from the spirit and scope of the invention. The scope is subject to the definition of the scope of the patent application.

1, 3. . . Backlight module

10. . . Light guide

100a. . . First entrance surface

100b. . . Glossy surface

100c. . . Second entrance surface

102. . . Reflective pattern

12. . . First light emitting diode

14. . . Diffusion sheet

16a, 16b, 16c, 16d, 16e. . . Optical diaphragm

160. . . Base

160a. . . First side

160b. . . Second side

162. . . First structure

162a. . . Curved peak

164. . . Second structure

164a. . . Straight crest

18. . . Second light emitting diode

36a, 36b, 36c, 36d, 36e. . . Optical diaphragm

362, 562. . . First structure

362a, 562a. . . Micro-diffusion structure

56a, 56b, 56c, 56d, 56e. . . Optical diaphragm

A. . . amplitude

C. . . Midline

H. . . Horizontal width

L. . . Moving average

P. . . End point

S. . . Protruding height

V1. . . Vertical height

V2. . . Vertical height

W. . . wavelength

FIG. 1 is a side view showing a backlight module according to an embodiment of the invention.

Fig. 2 is a perspective view showing the optical film of Fig. 1.

Fig. 3A is a top view showing one of the first 稜鏡 structures of the optical film of Fig. 2.

FIG. 3B is a perspective view showing the first 稜鏡 structure in FIG. 3A, wherein the first 稜鏡 structure is in the form of left and right yaw.

FIG. 3C is a perspective view showing another embodiment of the first 稜鏡 structure in FIG. 3A, wherein the first 稜鏡 structure is in the form of ups and downs.

Fig. 4A is a top view showing the optical film of Fig. 2.

Figure 4B is a top plan view showing another embodiment of the optical film of Figure 4A.

Figure 4C is a top plan view showing another embodiment of the optical film of Figure 4A.

FIG. 5 is a side view showing a backlight module according to another embodiment of the present invention.

Fig. 6A is a top view showing the optical film of Fig. 5.

Figure 6B is a top plan view showing another embodiment of the optical film of Figure 6A.

Figure 7 is a side elevational view showing another embodiment of one of the first crucible structures of the optical film of Figure 1.

Fig. 8A is a top view showing an embodiment of the optical film of Fig. 2, which adopts the first structure of Fig. 7.

Figure 8B is a top plan view showing another embodiment of the optical film of Figure 8A.

Figure 8C is a top plan view showing another embodiment of the optical film of Figure 8A.

Figure 8D is a top view showing another embodiment of the optical film of Figure 8A.

Figure 8E is a top plan view showing another embodiment of the optical film of Figure 8A.

Figure 9A is a top plan view showing another embodiment of the optical film of Figure 8A.

Figure 9B is a top plan view showing another embodiment of the optical film of Figure 9A.

Figure 9C is a top plan view showing another embodiment of the optical film of Figure 9A.

Figure 9D is a top view showing another embodiment of the optical film of Figure 9A.

Figure 9E is a top plan view showing another embodiment of the optical film of Figure 9A.

16a. . . Optical diaphragm

160. . . Base

160a. . . First side

160b. . . Second side

162. . . First structure

162a. . . Curved peak

164. . . Second structure

164a. . . Straight crest

Claims (27)

An optical film comprising: a substrate having two opposite first sides and a second side; and a plurality of first 稜鏡 structures disposed on the substrate and arranged by the first side toward the second side, Each of the first 稜鏡 structures has a bending peak having a degree of fluctuation; wherein the degree of fluctuation of the first 稜鏡 structures is gradually decreased from the first side toward the second side. The optical film of claim 1, wherein each of the bending peaks has two end points, and the end points of each of the bending peaks define a moving line, and each of the bending peaks is formed corresponding to the moving average A plurality of waves, each of the plurality of curved peaks having an average wavelength, each of the degrees of fluctuation decreasing as the corresponding average wavelength increases. The optical film of claim 2, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the first side structure of the first side is The average wavelength is generally between 10% and 50% of the average wavelength of the first tantalum structure at the centerline. The optical film of claim 1, wherein each of the bending peaks has two end points, and the end points of each of the bending peaks define a moving line, and each of the bending peaks is formed corresponding to the moving average A plurality of waves, each of the plurality of curved peaks having an average amplitude, each of the degrees of fluctuation increasing as the corresponding average amplitude increases. The optical film of claim 4, wherein each of the first structures has an average vertical height that is less than 20% of the average vertical height. The optical film of claim 4, wherein each of the first structures has an average horizontal width that is less than 20% of the average horizontal width. The optical film of claim 4, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the first 稜鏡 structure of the center line The average amplitude is substantially 10% to 50% of the average amplitude of the first tantalum structure on the first side. The optical film of claim 1, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the first 稜鏡 structure is located on the first side Between the midlines. The optical film of claim 1, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the fluctuations of the first 稜鏡 structures are respectively The first side and the second side are tapered toward the center line. The optical film of claim 1, further comprising a plurality of second 稜鏡 structures disposed on the substrate, each of the second 稜鏡 structures having a flat peak, each of the second 稜鏡The structure is located between any two adjacent first 稜鏡 structures, and the number of the second 稜鏡 structures between any two adjacent first 稜鏡 structures is oriented by the second side The first side is decreasing. The optical film of claim 10, wherein the center of the substrate has a center line, the center line is between the first side and the second side, and the second side structures are located on the second side Between the midlines. The optical film of claim 10, wherein the center of the substrate has a center line, the center line is between the first side and the second side, and the second 稜鏡 structure is located at any two adjacent The number between the first raft structures is gradually increased from the first side and the second side toward the center line. An optical film comprising: a substrate having two opposite first sides and a second side; a plurality of first 稜鏡 structures disposed on the substrate and aligned by the first side toward the second side; a plurality of micro-diffusion structures disposed on the surfaces of the first structures, such that each of the first structures has a degree of light diffusion; wherein the degrees of light diffusion of the first structures are determined by The first side tapers toward the second side. The optical film of claim 13, wherein the micro-diffusion structures on each of the first structures have an average protrusion height, and each of the degrees of light diffusion decreases as the corresponding protrusion height decreases. The optical film of claim 14, wherein the first meander structures have a vertical height, the average protruding heights being less than 80% of the vertical height. The optical film of claim 14, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the first side structure of the first side is The average protrusion height of the micro-diffusion structures is substantially 10% to 50% of the average protrusion height of the micro-diffusion structures of the first 稜鏡 structure of the center line. The optical film of claim 13, wherein the micro-diffusion structures on each of the first 稜鏡 structures have an average density, the average density being the number of the micro-diffusion structures included per unit area, each The degree of light diffusion decreases as the corresponding average density decreases. The optical film of claim 17, wherein the center of the substrate has a center line, the center line being located between the first side and the second side, on the first side structure of the first side The average density of the micro-diffusion structures is substantially 10% to 50% of the average density of the micro-diffusion structures on the first 稜鏡 structure of the centerline. The optical film of claim 13, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the first 稜鏡 structure is located on the first side Between the midlines. The optical film of claim 13, wherein the center of the substrate has a center line, the center line is located between the first side and the second side, and the degree of light diffusion of the first 稜鏡 structure The first side and the second side are gradually decreased toward the center line. The optical film of claim 13, further comprising a plurality of second 稜鏡 structures disposed on the substrate, each of the second 稜鏡 structures having a smooth surface, each of the second 稜鏡 structures being located Between any two adjacent first 稜鏡 structures, and the number of the second 稜鏡 structures between any two adjacent first 稜鏡 structures, from the second side toward the first One side is decreasing. The optical film of claim 21, wherein the center of the substrate has a center line, the center line is between the first side and the second side, and the second side structures are located on the second side Between the midlines. The optical film of claim 21, wherein the center of the substrate has a center line, the center line is between the first side and the second side, and the second 稜鏡 structure is located at any two adjacent The number between the first raft structures is gradually increased from the first side and the second side toward the center line. The optical film of claim 13, wherein the micro-diffusion structures are spherical or polygonal. A backlight module includes: a light guide plate having a first light incident surface and a light exiting surface, wherein the first light incident surface is connected to the light emitting surface; and the plurality of first light emitting diodes are along the first a light-incident surface; a diffusion sheet disposed on the light-emitting surface; and an optical film comprising: a substrate disposed on the diffusion sheet; and a plurality of first 稜鏡 structures disposed on the substrate and along The first light emitting diodes are arranged to extend in a direction in which the first germanium structures adjacent to the light emitting diodes are diffused more than the light emitting diodes away from the light emitting diodes. The backlight module of claim 25, wherein one of the first meander structures has a curved top corner line to form a different degree of diffusion. The backlight module of claim 25, wherein one of the first germanium structures has a plurality of micro-diffusion structures to form different degrees of diffusion.