A backlight module having optical film with inclined structure

Abstract

A backlight module includes a substrate, a plurality of light-emitting elements, and at least one optical film. The light-emitting elements are arranged on the substrate in a first direction and a second direction, respectively. The optical film includes a first surface and a second surface. The first surface has a plurality of conical structures, the edges of which form a plurality of first ridges, the first ridges forming an angle with the first direction. The second surface faces the substrate relative to the first surface.

Description

Technical Field

[0001] A backlight module, particularly a backlight module for use in a display. Prior Technology

[0002] The backlight module is one of the main components of modern LCD screens. It contains multiple light-emitting elements that form the image displayed on the LCD screen. To ensure more uniform light distribution from these elements and improve the quality of the displayed image, a diffuser plate is incorporated into the direct-lit backlight module. This diffuser plate has textured surfaces that utilize physical phenomena such as light refraction, reflection, and scattering to distribute the light more evenly. As technology advances to improve display contrast, Mini LEDs are gradually replacing ordinary LEDs as the light-emitting elements in backlight modules. Mini LEDs have a smaller light-emitting area, making it difficult for traditional diffusers to effectively disperse the light source. Please refer to Figures 1A to 1D. Figure 1A illustrates a backlight module, Figure 1B shows a schematic diagram of a traditional microstructure without offset structure, Figure 1C shows the optical simulation results, and Figure 1D shows a traditional optical film without offset structure. This backlight module 10 includes a substrate 11, Mini LEDs 12, and a traditional optical film without offset structure 13. The microstructure 14 of this traditional optical film 13 without offset structure corresponds to the arrangement of the Mini LEDs 12. The optical simulation results show that there are still relatively dim areas in the region 15 between the Mini LEDs 12, indicating poor light performance. Therefore, how to solve the above problem is something that those with general knowledge in this field should consider. Summary of the Invention

[0003] This invention provides a backlight module with a diffuser plate having an offset microstructure, which can effectively improve the light diffusion performance. This invention provides a backlight module, including a substrate, a plurality of light-emitting elements, and at least one optical film. The light-emitting elements are arranged on the substrate in a first direction and a second direction. The optical film includes a first surface and a second surface. The first surface has a plurality of conical structures forming a plurality of first ridges, the first ridges forming an angle with the first direction. The second surface faces the substrate relative to the first surface. The angle is θ, the distance between a light-emitting element in the first direction and an adjacent light-emitting element is X, the distance between a light-emitting element in the second direction and an adjacent light-emitting element is Y, and the angle θ ranges from... . The aforementioned backlight module, among which, . In the aforementioned backlight module, the cone-shaped structure is a square pyramid. In the aforementioned backlight module, the second surface further includes a plurality of cylindrical structures, and the cylindrical structures further include a second ridge line, which is deviated from the horizontal edge of the optical film at the angle described above. The aforementioned backlight module also includes at least one prism, disposed above the optical film. In the aforementioned backlight module, the light-emitting element is a miniature light-emitting diode. In the aforementioned backlight module, the thickness of the optical film is 0.05-0.5 mm. In the aforementioned backlight module, the optical film is made of polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), or a composite material of PC, PMMA, and PET. The backlight module of this invention can provide better light performance, while reducing the density of light-emitting elements to achieve comparable light performance, further reducing the manufacturing cost of the backlight module. Simple Explanation of the Diagram

[0004] Figure 1A shows a backlight module. Figure 1B shows a schematic diagram of the diffuser plate microstructure. Figure 1C shows the results of the optical simulation. Figure 1D shows a conventional optical film without a misalignment structure. Figure 1E shows a conventional optical film without a misaligned cylindrical structure. Figure 2A shows an optical film of one embodiment. Figure 2B shows a partial enlarged view of the optical film. Figure 2C shows a side cross-sectional view of the optical film. Figures 3A and 3B show schematic diagrams of the oblique cone structure. Figure 3C shows a different arrangement of light-emitting elements. Figure 4A illustrates the backlight module of the first embodiment. Figure 4B shows an optical simulation diagram of the backlight module of the first embodiment. Figure 5A illustrates the backlight module of the second embodiment. Figure 5B shows an optical simulation diagram of a backlight module without offset microstructures paired with a prism. Figure 5C is an optical simulation diagram of the backlight module in the second embodiment. Figure 6A shows a back view of an optical film according to another embodiment. Figure 6B shows a partial enlarged view of the back side of the optical film. Figure 6C shows a side cross-sectional view of the optical film. Figure 6D illustrates a cylindrical structure of another embodiment. Figure 7A shows the backlight module of the third embodiment. Figure 7B shows an optical simulation diagram without the off-center microstructure. Figure 7C is an optical simulation diagram of the backlight module in the third embodiment. Figure 8A illustrates the backlight module of the fourth embodiment. Figure 8B shows an optical simulation diagram of a backlight module without offset microstructures. Figure 8C is an optical simulation diagram of the backlight module in the fourth embodiment. Figures 9A and 9B show partial schematic diagrams of the optical film of the fifth embodiment. Figures 9C and 9D illustrate the optical film of the sixth embodiment. Implementation

[0005] In view of this, the present invention provides a backlight module in which the optical film has a microstructure corresponding to the angular offset of the Mini LED array, which can effectively improve the light diffusion of Mini LED and improve light performance. Please refer to Figure 4A, which illustrates a backlight module according to a first embodiment of the present invention. The backlight module 100 of the first embodiment includes a substrate 120, a plurality of light-emitting elements 130, and a plurality of optical films 110. The light-emitting elements 130 are disposed on the substrate 120, and are arranged on the substrate 120 in a first direction and a second direction, respectively. The substrate 120 is, for example, a flexible substrate. Referring to Figure 3B, the light-emitting elements 130 are arranged in a first direction 131 and a second direction 132, respectively, with the first direction 131 and the second direction 132 being perpendicularly intersecting. In this embodiment, the light-emitting element 130 is, for example, a light-emitting diode (LED), and in a preferred embodiment, the light-emitting element 130 is a mini LED. An optical film 110 is disposed above the light-emitting element 130. In a preferred embodiment, the thickness of the optical film 110 is 0.05-0.5 mm, and the number of optical films 110 is 3-5. Furthermore, the material of the optical film 110 can be polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), or a stacked composite material of PC, PMMA, and PET. Please refer to Figures 2A to 2C. Figure 2A shows an optical film of one embodiment, Figure 2B shows a partial enlarged view of the optical film, and Figure 2C shows a side cross-sectional view of the optical film. The optical film 110 includes a first surface 111 and a second surface 112, which are disposed opposite to each other, wherein the second surface 112 is disposed facing the light-emitting element 130. The first surface 111 of the optical film 110 also includes a plurality of conical structures 113, each conical structure 113 having a vertex 114 that extends toward the second surface 112. That is, the conical structures 113 are recessed into the first surface 111. Further, in this embodiment, the conical structures 113 are recessed quadrangular pyramids. These conical structures 113 are closely arranged to form a plurality of first ridges 116, the first ridges 116 forming an angle with a first direction. Please refer to Figures 3A and 3B, which illustrate schematic diagrams of the tilted conical structure 113. The tilt angle of the conical structure 113 is related to the arrangement of the light-emitting elements 130. Please refer to Figure 3A first. The embodiment in Figure 3A uses a quadrangular pyramid as an example for the conical structure 113, and to maintain clarity, the vertex 114 is not shown in Figure 3A. The edges of the multiple conical structures 113 form multiple first ridge lines 116. The first ridge lines 116 form an angle θ with the first direction 131 (indicated by dashed lines). Next, referring to Figure 3B, the angle θ is determined by the arrangement of the light-emitting elements 130, specifically by the angle between one of the light-emitting elements 130 and the angled light-emitting element 130. In other words, the tangent of angle θ is equal to the distance Y of the light-emitting elements 130 in the second direction 132 divided by the distance X of the light-emitting elements 130 in the first direction 131. Therefore, the tilt angle θ of the conical structure 113 corresponds to the arrangement of the light-emitting elements 130. In other words, the arctangent function of the distance Y of the light-emitting element 130 in the second direction 132 divided by the distance X of the light-emitting element 130 in the first direction 131 is the angle θ, i.e. Furthermore, the angle θ is allowed a certain range of tolerance; in a preferred embodiment, the tolerance is 10˚, that is, angle θ ± 10˚. Specifically, this means... . Please refer to Figure 3C, which illustrates a different arrangement of light-emitting elements. In the embodiment of Figure 3C, the light-emitting elements 130 are arranged in a diamond array. However, in this embodiment, the light-emitting elements 130 are still arranged along a first direction 131 and a second direction 132. The definition of angle θ is still related to the distance Y' of the light-emitting elements 130 in the second direction 132 and the distance X' of the light-emitting elements 130 in the first direction, that is... Furthermore, the first ridge 116 of the conical structure 113 on the optical film 110 will form an angle θ with the arrangement of the light-emitting elements 130. Please refer to Figures 4A and 4B. Figure 4A illustrates the backlight module of the first embodiment. Figure 4B illustrates an optical simulation diagram of the backlight module of the first embodiment. The backlight module 100 of the first embodiment includes three optical films 110 and has an oblique conical structure 113. Compared with the conventional optical simulation diagram of Figure 1C, it can be seen from the optical simulation diagram of Figure 4B that the central region 16 has more light spots, replacing the original dim performance. It is evident that the optical films 110 improve the light diffusion performance of the light-emitting element 130. Please refer to Figure 5A, which illustrates the backlight module of the second embodiment. The backlight module 200 of the second embodiment has multiple prisms 150 disposed above the optical film 110. Each prism 150 includes a first prism 151 and a second prism 152, wherein the structural directions of the first prism 151 and the second prism 152 are orthogonal. Specifically, the first prism 151 and the second prism 152 include directional microstructures, and when disposed, the extension directions of the microstructures of the two prisms are perpendicular to each other. Next, please refer to Figures 5B and 5C. Figure 5B shows an optical simulation diagram of the prior art. Figure 5B is based on the backlight module 200 of the second embodiment, with the optical film 110 replaced by a conventional optical film 13 without a bias structure (as shown in Figure 1D), resulting in an optical simulation diagram. Figure 5C is an optical simulation diagram of the backlight module of the second embodiment. By comparing the optical simulation diagrams of Figures 5B and 5C, it can be seen that in Figure 5B, the high-brightness area is smaller, and most of it is concentrated at the light-emitting point. In contrast, the high-brightness area in Figure 5C is significantly diffused, effectively diffusing light to the central area. Please refer to Figures 6A to 6C. Figure 6A shows a back view of an optical film according to another embodiment. Figure 6B shows a partially enlarged view of the back of the optical film. Figure 6C shows a side cross-sectional view of the optical film. In this embodiment, the optical film 310 includes a first surface 311 and a second surface 312, and the first surface 311 includes a plurality of conical structures 313. The technical features of the first surface 311 and the conical structures 313 are equivalent to those of the embodiment in Figure 2C, and will not be repeated here. The feature of this embodiment is that the second surface 312 also includes a plurality of lenticular cylindrical structures 317. Furthermore, the lenticular cylindrical structure 317 also includes a second ridge 318. The second ridge 318 is deviated from the first direction 131 of the light-emitting element 130 at an angle θ, that is, the arrangement direction of the lenticular cylindrical structure 317 is equivalent to that of the conical structure 313 of the first surface 311. Please refer to Figure 6D, which illustrates a cylindrical structure 317' of another embodiment. This cylindrical structure 317' is a curved surface formed by the overlapping of cylinders in different directions, and therefore has two second edges 318a and 318b, representing two cylinders in different directions. The two second edges 318a and 318b are preferably perpendicular to each other, and one of the second edges 318a is deflected at an angle θ from the first direction 131 of the light-emitting element 130. Please refer to Figure 1E, which illustrates a conventional optical film with a cylindrical structure. Comparing Figures 6A and 1E, it can be seen that in this embodiment (Figure 6A), the cylindrical structure 317 of the optical film 310 is angularly offset from the first direction 131 of the light-emitting element 130. In contrast, the cylinders of the conventional optical film 13' (Figure 1E) without an offset cylindrical structure are arranged in parallel. Please refer to Figure 7A, which illustrates the backlight module of the third embodiment. The backlight module 300 of the third embodiment includes multiple optical films 310 disposed above the light-emitting element 130, and the cylindrical structure 317 of the optical films 310 is disposed facing the light-emitting element 130. Next, please refer to Figures 7B and 7C. Figure 7B shows an optical simulation diagram of the prior art, which is an optical simulation diagram generated by replacing the optical film 310 with the conventional non-offset cylindrical optical film 13' shown in Figure 1E, based on the backlight module 300 of the third embodiment. Figure 7C is an optical simulation diagram of the backlight module of the third embodiment. As can be seen from Figure 7B, the light is relatively concentrated at the light-emitting point, while the central area is obviously dark. As can be seen from Figure 7C, after offsetting the conical structure 113 and the cylindrical structure 317, the light can be distributed more evenly and the darkness in the central area can be filled, effectively improving the light performance. Please refer to Figure 8A, which illustrates the backlight module of the fourth embodiment. The backlight module 400 of the fourth embodiment has a prism 150 disposed above the optical film 310. The technical features of the prism 150 are equivalent to those of the second embodiment (Figure 5A), and will not be repeated here. Next, please refer to Figures 8B and 8C. Figure 8B illustrates an optical simulation diagram of the prior art, which is an optical simulation diagram generated by replacing the optical film 310 with the conventional non-offset cylindrical optical film 13' shown in Figure 1E, based on the backlight module 400 of the fourth embodiment. Figure 8C is an optical simulation diagram of the backlight module of the fourth embodiment. As can be seen from Figure 8B, compared to Figure 7B, the light is more dispersed after applying the prism 150, but it can still be seen that the light is still concentrated around the light-emitting area. In Figure 8C, it can be seen that after offsetting the conical structure 113 and the cylindrical structure 317, the light can be distributed more evenly. Please refer to Figures 9A to 9D. Figures 9A and 9B show partial schematic diagrams of the optical film of the fifth embodiment, and Figures 9C and 9D show the optical film of the sixth embodiment. In the aforementioned embodiments, the conical structure 113 is a square pyramid, but it is not limited to this; different types of pyramids can also be used to form the conical structure 113. The optical film 500 in Figures 9A and 9B uses a concave equilateral triangular pyramid as the conical structure 113, with one side of the triangular pyramid as the first ridge 116, and it is deflected at an angle θ from the first direction 131 of the light-emitting element 130. In Figures 9C and 9D, the optical film 600 is a concave isosceles triangular pyramid 601 as a conical structure 113. The shape of the isosceles triangular pyramid 601 is drawn in the diagonal area in Figures 9C and 9D, and one of the base sides of the isosceles triangular pyramid 601 is used as the first edge 116, which is deflected at an angle θ from the first direction 131 of the light-emitting element 130. The backlight module provided by this invention includes optical films 110 and 310, which have offset conical structures 131 and cylindrical structures 317, effectively improving the light diffusion effect of the light-emitting element 130 and allowing the light to better cover the display area. Compared with conventional backlight modules, the backlight module of this invention can provide better light performance, while achieving comparable light performance with a lower density of light-emitting elements 130, further reducing the manufacturing cost of the backlight module. The invention has been described above, but it is not intended to limit the scope of the patent rights claimed in this work. The scope of patent protection shall be determined by the appended scope of the patent application and its equivalent fields. Any modifications or refinements made by those skilled in the art without departing from the spirit or scope of this patent are equivalent changes or designs made under the spirit disclosed in this work and should be included within the scope of the patent application described below.

[0006] 10: Backlight Module 11: Reflective sheet 12: Mini LED 13: Traditional optical films with diffusion effects 13': Traditional optical films with cylindrical structures 14: Microstructure 15: Area 100, 200, 300, 400, 500, 600: Backlight Module 110, 310: Optical films 111, 311: First surface 112, 312: Second surface 113, 313: Conical structure 114, 314: Vertex 116: First ridge line 317, 317': Cylindrical structure 318, 318a, 318b: Second ridge line θ: angle X, Y: Distance 120:Substrate 130: Light-emitting element 131: First Direction 132: Second Direction 601: Isosceles triangle

Claims

1. A backlight module, comprising: One substrate; Multiple light-emitting elements are arranged on the substrate in a first direction and a second direction, respectively; The system comprises multiple optical films stacked perpendicularly to each other, each optical film including: a first surface having multiple concave conical structures, the edges of which form multiple first ridges, the first ridges forming an angle (θ) with the first direction; and a second surface facing the substrate relative to the first surface, the second surface further including multiple cylindrical structures; wherein each cylindrical structure further includes a second ridge, the second ridge forming an angle (θ) with the first direction; wherein the distance between the light-emitting element in the first direction and an adjacent light-emitting element is X, the distance between the light-emitting element in the second direction and an adjacent light-emitting element is Y, and the angle (θ) ranges from [value missing].

2. The backlight module as described in claim 1, wherein, The angle (θ) is...

3. The backlight module as described in claim 1, wherein, The cone-shaped structure is a concave four-cornered pyramid.

4. The backlight module as described in claim 1, wherein, The cone-shaped structure is a concave polygonal pyramid.

5. The backlight module as described in claim 1, wherein, This cylindrical structure is a curved surface formed by the overlapping of cylinders in different directions.

6. The backlight module as described in claim 1 further includes at least one prism disposed above the optical film.

7. The backlight module as described in claim 1, wherein, The light-emitting element is a miniature light-emitting diode.

8. The backlight module as described in claim 1, wherein, The thickness of the optical film is 0.05-0.5 mm.

9. The backlight module as described in claim 1, wherein, The optical film is made of polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), or a composite material of PC, PMMA, and PET.

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