Optical film, backlight module and display device

Abstract

The utility model provides a kind of optical film, backlight module and display device.The optical film is suitable for installation and abuts to the inner wall of frame body.The optical film includes body part and at least two first abutting parts.The body part has the shape corresponding with the inner wall of frame body, and forms first gap between the inner wall in installation state in first direction.Each first abutting part is extended from the opposite sides of body part respectively, and second gap is formed between the outside of each first abutting part and the inner wall.The second gap is smaller than the first gap.The body part has optical surface, a plurality of strip structures are provided on the optical surface, and each first abutting part is located on the opposite sides of the extension direction of the plurality of strip structures.By this configuration, the optical film can be stably positioned in the frame body, and the optical performance of backlight module is maintained.

Description

[0001] This application claims priority to Chinese Patent Application No. 202522074418.3, filed on September 26, 2025, entitled "Optical Film, Backlight Module and Display Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to the technical field of backlighting, and in particular to an optical film with an abutment portion, and its application in backlight modules and display devices. Background Technology

[0003] In backlight modules, various optical films are usually set to adjust the light transmission path and improve the light output quality.

[0004] However, when traditional optical films are installed in the frame, their position often shifts due to factors such as assembly tolerances, thermal expansion, or structural loosening, resulting in reduced or unstable optical performance. Utility Model Content

[0005] The purpose of this invention is to provide an optical film and its application in backlight modules and display devices. By changing the edge shape of the optical film, a limiting effect is naturally generated during assembly, thereby improving the positioning stability of the film, reducing offset, and effectively suppressing optical abnormalities caused by offset, thus solving the problems existing in the prior art.

[0006] To achieve the above objectives, this utility model provides an optical film. This optical film is suitable for mounting and abutting against the inner wall of a frame. The optical film includes a body portion and at least two first abutting portions. The body portion has a shape corresponding to the inner wall of the frame and forms a first gap with the inner wall in a first direction when mounted. Each first abutting portion extends from opposite sides of the body portion, and a second gap is formed between the outer side of each first abutting portion and the inner wall, the second gap being smaller than the aforementioned first gap. The body portion has an optical surface, on which a plurality of strip-shaped structures are provided, and each first abutting portion is located on opposite sides of the extending direction of the plurality of strip-shaped structures.

[0007] In one embodiment of this utility model, the aforementioned body portion may have opposing near-incident light side and back-incident light side, and two opposing abutting sides connecting the near-incident light side and the back-incident light side. At least one first abutting portion is provided on each abutting side, and each first abutting portion is respectively provided on two abutting sides opposite to each other in the extending direction of the strip structure.

[0008] In one embodiment of the present invention, at least one of the first abutting portions described above may be disposed closer to the reflected light side than to the near-light side side.

[0009] In one embodiment of this invention, the optical film may further include at least one second abutment portion. The second abutment portion extends from the light-reflecting side of the body portion toward the frame along a second direction, and the second direction is perpendicular to the first direction. A third gap is formed between the body portion and the inner wall in the second direction, and a fourth gap is formed between the outer side of the second abutment portion and the inner wall, the fourth gap being smaller than the third gap.

[0010] In one embodiment of this utility model, the number of the second abutting part and the first abutting part can both be two. One of the second abutting parts and one of the first abutting parts are connected at the junction of the light-reflecting side and the abutting side to form an integral structure, and the other second abutting part and the other first abutting part form another integral structure at another junction.

[0011] In one embodiment of this utility model, the first gap and the second gap can be set according to the thermal expansion coefficient of the optical film material and the temperature range of the operating environment, so as to accommodate the dimensional changes of the optical film caused by thermal expansion.

[0012] In one embodiment of this utility model, the size ratio of the first gap to the second gap can be set to 2:1.

[0013] This invention also provides a backlight module. The backlight module includes at least one of the aforementioned optical films, a frame, and a light source. The frame is used to house the optical film, while the light source is disposed on one side of the optical film.

[0014] In one embodiment of this invention, the backlight module may include two optical films. The strip-shaped structures of each optical film extend at an angle to each other, and the offset of the angle is less than 6 degrees.

[0015] In one embodiment of the present invention, the first contact portion of the two optical films described above may be configured differently, for example, by differences in position or shape.

[0016] In another backlight module design of this utility model, the backlight module includes a frame, at least one optical film, and a light source. The frame has at least two planar inner walls. The optical film is disposed within the frame and includes a body portion and at least two abutting portions. The body portion has an optical surface with multiple strip-shaped structures, the two ends of which extend toward opposite abutting sides. The abutting portions extend from the body portion toward the planar inner walls. The light source is disposed on one side of the optical film.

[0017] In one embodiment of this invention, the light source described above can be disposed on the near-incident light side of the optical film. This near-incident light side is connected to the abutting side and is closer to the light source than the abutting side.

[0018] In one embodiment of this utility model, the aforementioned abutting portions can also be disposed at the corner of the main body of the optical film, and the corner of the frame is a non-recessed planar structure.

[0019] In one embodiment of the present invention, a first gap may be formed between the main body and the planar inner wall, and a second gap may be formed between the outer side of each abutting part and the planar inner wall, and the second gap is smaller than the first gap.

[0020] In addition, this utility model also provides a display device. The display device includes any of the aforementioned backlight modules and a display panel disposed on one side of the backlight module.

[0021] As described above, the optical film provided by this invention has an abutment portion formed on its body, allowing it to directly limit each other with the planar inner wall of the frame. This reduces the gap between the optical film and the frame and provides a multi-directional positioning effect, thereby ensuring the stable installation of the optical film within the frame and preventing displacement due to assembly tolerances or thermal expansion. When the optical film is applied to a backlight module, it can maintain overall light emission uniformity and optical quality, further improve assembly efficiency and reduce process costs, and is applicable to various display devices. Attached Figure Description

[0022] Figure 1A and Figure 1B These are schematic diagrams of the backlight module according to two embodiments of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of a backlight module according to another embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of a backlight module according to another embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of a display device according to another embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram showing the displacement of the optical film relative to the frame according to this utility model. Detailed Implementation

[0027] To make the above and other objects, features, and advantages of this utility model more apparent and understandable, preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Furthermore, the directional terms used in this utility model, such as up, down, top, bottom, front, back, left, right, inside, outside, side, surrounding, center, horizontal, transverse, vertical, longitudinal, axial, radial, uppermost, or lowermost, are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for the purpose of explaining and understanding this utility model, and not for limiting it.

[0028] Please refer to Figure 1A The backlight module 1 of this embodiment mainly includes a frame 11, an optical film 12, and a light source 13. The frame 11 has an inner wall 11a, the optical film 12 is disposed inside the frame 11, and the light source 13 is disposed on one side of the optical film 12. The optical film 12 includes a body portion 121 and at least two first abutment portions 122. The body portion 121 has a shape corresponding to the inner wall 11a of the frame 11. In a specific example, the inner wall 11a of the frame 11 and the body portion 121 are similar in shape to rectangles. Each first abutment portion 122 extends from opposite sides of the body portion 121, wherein the body portion 121 has an optical surface 121a, on which a plurality of strip structures 123 are provided for controlling the light distribution, and the first abutment portions 122 are disposed on opposite sides of the strip structures 123. For example, the strip structure 123 extends toward the opposite sides of the body portion 121, and the strip structure 123 may also be arranged at intervals between the opposite sides of the body portion 121.

[0029] In the installed state, a first gap G1 is formed between the main body 121 and the inner wall 11a in the first direction D1, and a second gap G2 is formed between the outer surface of each first abutment portion 122 and the inner wall 11a, and the second gap G2 is smaller than the first gap G1. It should be noted that the existence of this first gap G1 is to accommodate assembly tolerances and to reserve space to cope with the thermal expansion of the optical film 12 due to temperature changes, preventing the optical film 12 from being compressed and warped. The two first abutment portions 122 can be considered as parts protruding outward from the basic contour of the main body 121; therefore, the second gap G2 is smaller than the first gap G1. With this configuration, the optical film 12 is positioned by the first abutment portions 122, limiting its displacement and rotation within the frame 11, while preventing excessive compression caused by the entire main body 121 being fully fitted to the inner wall 11a. This effectively avoids excessive compression caused by thermal expansion or differences in assembly dimensions and ensures the stability of the optical film 12 within the frame 11. Furthermore, even under certain extreme conditions of thermal expansion, the first contact portion 122 will only briefly contact the inner wall 11a, without causing the optical film 12 to be subjected to large-area compression or wrinkling. In this embodiment, the first direction D1 refers to the arrangement direction parallel to the light source 13. The light source 13 is located on the side of the body portion 121, between the sides where the two first contact portions 122 are located. The extension direction of the strip structure 123 is approximately parallel to the arrangement direction of the light source 13, with an angular deviation of no more than 20 degrees.

[0030] Furthermore, the first abutment portion 122 can be formed by the geometric design of the edge of the body portion 121, such as a non-right-angled edge, chamfered edge, curved edge, or asymmetrical edge. This design allows the first abutment portion 122 to form a local protruding structure on the side facing the frame 11, which can effectively limit the displacement and rotation of the optical film 12, while also helping to maintain directional consistency when multiple optical films are stacked.

[0031] In one embodiment, such as Figure 1A As shown, the body portion 121 has opposing near-light-incident side surface 121b, reflective light-incident side surface 121c, and abutting side surface 121d connecting the near-light-incident side surface 121b and the reflective light-incident side surface 121c. At least one first abutting portion 122 is formed on each abutting side surface 121d, and each first abutting portion 122 is correspondingly disposed on opposite sides of the extension direction of the plurality of strip structures 123. For example, if the strip structures 123 are approximately along... Figure 1A The first abutment portion 122 extends horizontally and connects to the two abutment sides 121d, and is respectively disposed on the left and right sides of the optical film 12. With this arrangement, the first abutment portion 122 can effectively restrict the displacement of the optical film 12 in the extension direction of the strip structure 123, thereby improving its positioning stability within the frame 11.

[0032] It should be noted that the number or arrangement of the first contact parts in this embodiment can be determined according to requirements. For example, in Figure 1A In one embodiment, the first abutting portion 122 is symmetrically disposed on the opposite abutting side surface 121d, while Figure 1B In some embodiments, the first abutting portion 122 can be asymmetrically configured. For example, only one first abutting portion 122 near the reflected light side 121c can be provided on one abutting side 121d, while only one first abutting portion 122 near the near light side 121b can be provided on the other abutting side 121d, still achieving the same limiting effect. Figure 1A In a preferred embodiment, the first abutting portion 122 located on different abutting sides 121d is positioned close to the light-reflecting side 121c. This restricts the range of motion of the edge of the light-reflecting side 121c, causing the main displacement tendency of the optical film 12 within the frame 11 to be a slight oscillation on the near-light-reflecting side 121b. As a result, the distance between the near-light-reflecting side 121b and the light source 13 can be kept more consistent and stable, providing support and positioning for the optical film 12 away from the light-reflecting surface, preventing the film from rotating or tilting, further enhancing its stability within the frame 11, and effectively suppressing LED mura or light leakage caused by uneven spacing, thus improving the appearance of the display screen.

[0033] In one embodiment, the first gap G1 and the second gap G2 of the optical diaphragm 12 can be set according to the coefficient of thermal expansion of the optical diaphragm 12 material and the temperature range of its operating environment. By appropriately reserving gaps, the dimensional changes of the optical diaphragm 12 caused by thermal expansion can be accommodated, avoiding excessive compression, wrinkling, or warping within the frame 11. For example, the first gap G1 can be designed to accommodate the expected expansion of the optical diaphragm 12 at the highest operating temperature to avoid stress that could lead to wrinkles; while the second gap G2 can be set to be smaller so that the optical diaphragm 12 can still maintain effective restraint after cooling and shrinking.

[0034] Specifically, the relationship between the first gap G1 and the second gap G2 can be designed as a size ratio of approximately 2:1. In an exemplary calculation method, the values ​​of the first gap G1 and the second gap G2 can be calculated using the following formula: First gap G1 = (0.2828 + 3.5 × 10^( 4) × MD × ΔT) / 2 ± 0.05; Second gap G2 = (0.2828 + 3.5 × 10^( 4) × MD × ΔT) / 4 ± 0.05. Where MD (Machine Direction) is the coefficient of thermal expansion of the material in the first direction D1, and ΔT is the difference between the highest temperature of the accelerated life test (RA test) and room temperature. The above design method enables the optical film 12 to maintain good installation stability and optical performance under different temperature conditions, thereby improving the overall reliability of the backlight module 1.

[0035] In other embodiments, such as Figure 1A As shown, the optical film 12 may be provided with a second abutment portion 124. The second abutment portion 124 extends from the light-reflecting side 121c of the body portion 121 toward the frame 11 along the second direction D2. In this configuration, a third gap G3 is formed between the body portion 121 and the inner wall 11a of the frame 11 in the second direction D2, and a fourth gap G4 is formed between the outer side of the second abutment portion 124 and the inner wall 11a, and the fourth gap G4 is smaller than the third gap G3. Through the design of the second abutment portion 124, the optical film 12 is positioned closer to the light source 13 in the space of the frame 11, thereby maintaining the optical performance and brightness uniformity near the light-reflecting end of the optical film 12.

[0036] In one embodiment, the third gap G3 and the fourth gap G4 of the optical diaphragm 12 can be set according to the coefficient of thermal expansion of the optical diaphragm 12 material and the temperature range of its operating environment, so as to avoid excessive compression or warping of the optical diaphragm 12 within the frame 11 due to thermal expansion. Specifically, the relationship between the third gap G3 and the fourth gap G4 can be designed as a size ratio of approximately 2:1. In an exemplary calculation method, the values ​​of the third gap G3 and the fourth gap G4 can be calculated using the following formula: Third gap G3 = (0.2828 + 2.22 × 10^( 4) × TD × ΔT) / 2 ± 0.05; Fourth gap G4 = (0.2828 + 2.22 × 10^( 4) × TD × ΔT) / 4 ± 0.05. Where TD (Transverse Direction) is the coefficient of thermal expansion of the material in the second direction D2 (perpendicular to the first direction D1), and ΔT is the difference between the highest temperature during accelerated life testing (RA test) and room temperature. In this embodiment, the same optical film often has different coefficients of thermal expansion in different directions due to different manufacturing processes. Therefore, by substituting MD and TD, optical films using other manufacturing processes may also have the same coefficient of thermal expansion in different directions.

[0037] In one specific embodiment, for a backlight module applied to a 14–16 inch display device, the gaps of the optical film 12 can be designed as follows: First gap G1 = (0.2828 + 3.5 × 10^( 4) ×50 × 40) / 2≈0.5 mm; Second gap G2 = (0.2828 + 3.5 × 10^( 4) ×50 × 40) / 4≈ 0.25 mm; Third gap G3 = (0.2828 + 2.22 × 10^( 4) ×80 × 40) / 2≈ 0.5 mm; Fourth gap G4 =(0.2828 + 2.22 × 10^( 4) ×80 × 40) / 4 ≈ 0.25 mm. Considering process tolerances and material variations, the above gaps can also be set as range values ​​to improve assembly reliability and thermal expansion tolerance. For example, the first gap G1 can be 0.45~0.55 mm; the second gap G2 can be 0.2~0.3 mm; the third gap G3 can be 0.45~0.55 mm; and the fourth gap G4 can be 0.2~0.3 mm. In addition, the distance D5 between the near-light-incident side 121b of the optical film 12 and the light source 13 can be designed to be about 0.5 mm to ensure that the light from the light source 13 is effectively incident on the light-incident end of the optical film 12. At the same time, in conjunction with the positioning design of the first abutment part 122 and the second abutment part 124, the optical film 12 maintains a stable position within the frame 11, maintaining overall optical performance and brightness uniformity.

[0038] It should be noted that, although Figure 1A The image shows both the first abutment portion 122 and the second abutment portion 124. The optical film 12 primarily achieves its positioning function through the first abutment portion 122, while the second abutment portion 124 serves as an auxiliary positioning structure to further enhance the stability of the optical film near the light-incident end. The second abutment portion 124 can be selectively provided or omitted according to actual needs. Furthermore, the "configuration" of the first abutment portion 122 and the second abutment portion 124 can be adjusted as needed, including shape, placement position, size, or a combination thereof. Moreover, the shape of the first abutment portion 122 and the second abutment portion 124 is not limited to rectangles; it can also be arc-shaped or other irregular shapes to adapt to different optical film or frame design requirements.

[0039] Please also refer to Figure 2In one embodiment, the present invention provides another backlight module 2. The backlight module 2 includes a frame 21, an optical film 22, and a light source 23. The frame 21 has at least two planar inner walls 21a, the optical film 22 is disposed within the frame 21, and the light source 23 is disposed on one side of the optical film 22. The optical film 22 includes a body portion 221 and at least two abutting portions 222, each abutting portion 222 extending from the body portion 221 toward the planar inner wall 21a. The body portion 221 has an optical surface 221a, opposing near-incident light side surface 221b and reverse-incident light side surface 221c, and an abutting side surface 221d connecting the near-incident light side surface 221b and the reverse-incident light side surface 221c. The optical surface 221a has a plurality of strip structures 223, the two ends of which extend toward the two opposing abutting sides 221d of the body portion 221, respectively, to regulate the light distribution. By providing the abutment portion 222, the displacement of the optical film 22 within the frame 21 can be limited, preventing excessive offset of the strip structure 223 in its extending direction. More specifically, since the planar inner wall 21a of the frame 21 in this embodiment does not have a groove or protrusion designed to accommodate the optical film 22, the limiting function is completely transferred to the geometric design of the optical film 22 itself, allowing the frame 21 to use the simplest and lowest-cost planar right-angle structure. This design simplifies the supply chain, reduces mold costs, and accelerates product development. Compared to the conventional design where the frame must have grooves / protrusions corresponding to the lugs / holes on the optical film, which is prone to large-area wrinkling due to mechanical interference under thermal expansion conditions, easily causing optical defects that cannot be restored, this invention avoids this problem.

[0040] In this embodiment, a first gap G11 is formed between the main body 221 and the planar inner wall 21a, while a second gap G21 is formed between the outer surface of each abutment portion 222 and the planar inner wall 21a, and the second gap G21 is smaller than the first gap G11. This design allows the optical diaphragm 22 to be positioned by the abutment portion 222 and ensures the assembly stability of the optical diaphragm 22 within the frame 21. The calculation methods for the first gap G11 and the second gap G21 can refer to the aforementioned calculation methods for the first gap G1, the second gap G2 (or the third gap G3 and the fourth gap G4), and will not be repeated here.

[0041] In one embodiment, the light source 23 is disposed on the near-incident light side 221b of the optical diaphragm 22. The near-incident light side 221b is connected to the abutment side 221d and is closer to the light source 23 than the abutment side 221d, which ensures that the light source 23 directly corresponds to the near-incident light side 221b of the optical diaphragm 22.

[0042] exist Figure 2In this embodiment, each abutment portion 222 is disposed at a corner position of the main body portion 221, corresponding to the corner of the frame 21. Since the corner of the frame 21 is a non-recessed planar structure, the optical diaphragm 22 can reduce the gap between itself and the planar inner wall 21a of the frame 21 at the corner position through the abutment portion 222, and achieve a stable limiting effect when abutting against the planar inner wall of the frame 21.

[0043] Furthermore, the abutment portion 222 at the corner of the main body 221 can be composed of two abutment structures extending in different directions, namely, a first abutment portion 222a extending in the first direction D1 and a second abutment portion 222b extending in the second direction D2. The first abutment portion 222a and the second abutment portion 222b can be integrally connected at the junction of the light-reflecting side surface 221c and the abutment side surface 221d, so that the optical film 22 has a limiting function in two directions at the corner position. The abutment portions 222 at other corner positions can also adopt the same design. With this structure, the optical film 22 can not only maintain stable positioning, but also restrict rotation, thereby further improving assembly reliability.

[0044] In one application example, two or more optical films can be configured in the backlight module. For example... Figure 3As shown, the backlight module 3 includes a frame 31, optical films 321 and 322, a light source 33, and a light guide plate 34. The light guide plate 34, optical films 321 and 322 are stacked sequentially within the frame 31, and the light source 33 is disposed on one side of the light guide plate 34 and the optical films. The optical film 321 has a strip-shaped structure 321a, and its main body has abutment portions 321b on both sides of its extension direction relative to the strip-shaped structure 321a; similarly, the optical film 322 has a strip-shaped structure 322a, and its main body has abutment portions 322b on both sides of its extension direction relative to the strip-shaped structure 322a. Therefore, each optical film can be precisely positioned within the frame and the stacking direction can be maintained consistently. In one practical application, optical films 321 and 322 each have asymmetrical strip-shaped microstructures extending towards opposite sides of the main body. The slope of these asymmetrical strip-shaped microstructures is gentler relative to the slope away from the light source 33, causing the incident light angle to be deflected at a smaller angle towards the positive direction. This deflects and concentrates the light from the lower light guide plate 34 upwards, bringing it closer to the normal direction of the optical surface. The light emission angle falls between -40 degrees and +40 degrees. This application example... The optical films 321 and 322 in the light module are positioned by their abutting parts 321b and 322b, which limit their displacement and rotation in the frame 11. This allows for more precise control over the sway angle of the extension direction of the strip-shaped microstructure of the optical films 321 and 322, thereby achieving effective light collection. When the aforementioned backlight module is applied to an automotive display, it ensures that the driver's line of sight is not interfered with by the display screen in front of the passenger seat, thus ensuring driving safety.

[0045] In this embodiment, the abutment portion 321b of optical film 321 and the abutment portion 322b of optical film 322 can have different configurations. For example, they can be set in different positions or staggered to facilitate identification during assembly. Furthermore, the abutment portions 321b and 322b can also differ in size or shape, such as in length, width, or geometric contour. Through this differentiated configuration, not only can the position and orientation of each optical film be clearly distinguished during assembly, but the positioning stability of the optical films within the frame can also be enhanced, and the angular offset between the strip structure 321a of optical film 321 and the strip structure 322a of optical film 322 can be maintained at less than 6 degrees. More preferably, the rotational offset of the two optical films 321 and 322 can be controlled within a very small range (e.g., less than 2 degrees each), which can effectively prevent the attenuation of the overall backlight module brightness, thereby ensuring the optical performance of the backlight module.

[0046] It should be noted that, in the above embodiments, the light guide plate 34 may also be designed with the same or similar abutment structure as the abutment portion 321b of the optical film 321 or the abutment portion 322b of the optical film 322, so as to achieve the same positioning and limiting effect. Therefore, the "optical film" referred to in this utility model can not only cover prism sheets, but also light guide plates with light guiding function, and both can achieve precise positioning and assembly stability within the frame through the design of the abutment portion.

[0047] Please refer to Figure 4 This utility model also provides a display device 4. The display device 4 includes, as follows: Figure 3 The backlight module 3 is shown, and a display panel 41 is disposed on one side of the backlight module 3. By providing a uniform and stable light source through the backlight module 3, the display panel 41 can achieve the desired image display effect. It should be noted that the display device 4 shown in this embodiment is used in conjunction with the backlight module 3. However, in other embodiments, the display device may also be used with... Figure 1A The backlight module 1 shown, or as shown Figure 2 The backlight module 2 shown can also achieve the effect of uniform light output and improved display quality.

[0048] As described above, this invention, by forming an abutment portion on the main body of the optical film, allows it to directly restrain itself against the planar inner wall of the frame, ensuring the positioning and stability of the optical film within the frame without altering the original frame structure. Furthermore, by reducing the gap between the optical film and the inner wall of the frame through the abutment portion, and creating a multi-directional restraining effect at corners or sides, the optical film is less prone to positional shifts during assembly or operation due to assembly tolerances, thermal expansion, or loosening of the mechanism. This avoids the problem of optical film skewing and maintains the light output uniformity and optical quality of the backlight module.

[0049] It should be further explained that one of the features of this utility model is the use of gap differences for limiting control. The larger first and third gaps provide the optical film with the space required for assembly and thermal expansion, while the smaller second and fourth gaps allow the abutment portion to act as a "limiting block," enabling it to preferentially contact the inner wall of the frame when the optical film rotates or translates, thereby forming an effective limiting effect. Figure 5 As shown, when the optical film 22 attempts to rotate or translate, its movement is preferentially limited by the abutment portions 222 on both sides, because they contact the inner wall of the frame 21 before other parts of the main body 221, thus forming a stable constraint effect, which can limit the rotation angle of the optical film. By controlling the brightness within a very small range, the stability of the optical brightness is ensured, avoiding the risk of a decrease in the overall brightness of the backlight module due to angular deviation. Furthermore, the optical film of this invention has the advantages of simplified processing and high mold versatility because its contact part can directly cooperate with a general frame. It eliminates the need for additional positioning components, thereby improving assembly efficiency, reducing costs, and facilitating the precise stacking and positioning of multiple optical films.

[0050] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the appended claims.

[0051] List of reference numerals

[0052] 1: Backlight Module

[0053] 11: Frame

[0054] 11a: Inner wall

[0055] 12: Optical films

[0056] 121: Ontology part

[0057] 121a: Optical surface

[0058] 121b: Near-incident side view

[0059] 121c: Side of reflected light

[0060] 121d: Abutting the side

[0061] 122: First landing section

[0062] 123: Strip-like structure

[0063] 124: Second contact section

[0064] 13: Light source

[0065] 2: Backlight Module

[0066] 21: Frame

[0067] 21a: Planar inner wall

[0068] 22: Optical films

[0069] 221: Ontology

[0070] 221a: Optical surface

[0071] 221b: Near-incident light side view

[0072] 221c: Side of reflected light

[0073] 221d: Abutting the side

[0074] 222: Butt

[0075] 222a: First contact section

[0076] 222b: Second abutment section

[0077] 223: Strip-like structure

[0078] 23: Light source

[0079] 3: Backlight Module

[0080] 31: Frame

[0081] 321: Optical film

[0082] 321a: Strip-like structure

[0083] 321b: Abutment section

[0084] 322: Optical film

[0085] 322a: Strip-like structure

[0086] 322b: Abutment section

[0087] 33: Light source

[0088] 34: Light guide plate

[0089] 4: Display device

[0090] 41: Display panel

[0091] D1: First Direction

[0092] D2: Second Direction

[0093] G1: Gap

[0094] G11: Gap

[0095] G2: Gap

[0096] G21: Gap

[0097] G3: Gap

[0098] G4: Gap

[0099] Rotation angle.

Claims

1. An optical film suitable for mounting and abutting against the inner wall of a frame, characterized in that, The optical film comprises: The body portion has a shape corresponding to the inner wall and forms a first gap with the inner wall in a first direction in the installed state; and At least two first abutting portions are formed extending from opposite sides of the body portion, and a second gap is formed between the outer side of each first abutting portion and the inner wall, the second gap being smaller than the first gap. The body portion has an optical surface on which a plurality of strip structures are provided, and each first abutting portion is located on opposite sides of the plurality of strip structures.

2. The optical film according to claim 1, characterized in that, The main body has a near-light-incident side and a back-light-incident side, and two opposing abutting sides connecting the near-light-incident side and the back-light-incident side. Each abutting side is provided with at least one first abutting part, and each first abutting part is respectively provided on two abutting sides opposite to each other in the extension direction of the plurality of strip structures.

3. The optical film according to claim 2, characterized in that, The at least one first contact portion is closer to the reflected light side relative to the near-incident light side.

4. The optical film according to claim 2, characterized in that, It also includes at least one second abutting portion, which extends from the light-reflecting side of the body portion toward the frame along a second direction, and the second direction is perpendicular to the first direction. A third gap is formed between the body portion and the inner wall in the second direction, and a fourth gap is formed between the outer side of the second abutting portion and the inner wall. The fourth gap is smaller than the third gap.

5. The optical film according to claim 4, characterized in that, The number of the at least one second abutment and the number of the at least two first abutments are both two; One of the second abutting parts and one of the first abutting parts are connected at the junction of the light-reflecting side and the abutting side to form an integral structure; Another second abutting part and another first abutting part are connected at the junction of the light-reflecting side and the other abutting side to form another integral structure.

6. The optical film according to claim 1, characterized in that, The first gap and the second gap are set according to the thermal expansion coefficient of the optical film material and the temperature range of the operating environment, so that they can accommodate the dimensional changes of the optical film caused by thermal expansion.

7. The optical film according to claim 1, characterized in that, The size ratio of the first gap to the second gap is 2:

1.

8. A backlight module, characterized in that, Include: At least one optical film according to any one of claims 1 to 7; and A frame for housing the optical diaphragm; and A light source is disposed on one side of the optical film.

9. The backlight module according to claim 8, characterized in that, The number of at least one optical film is two, and there is an angle between the extension directions of the strip structure of each optical film, the offset of the angle being less than 6 degrees.

10. The backlight module according to claim 9, characterized in that, The configuration of the first abutment portion of one of the optical films is different from the configuration of the first abutment portion of the other optical film.

11. A backlight module, characterized in that, Include: A frame having at least two planar inner walls; At least one optical film disposed within the frame, the optical film comprising: The body has an optical surface, on which a plurality of strip structures are provided, the two ends of which extend toward two opposite abutting sides of the body. as well as At least two abutting portions are formed extending from the body portion toward the planar inner wall; and A light source is disposed on one side of the optical film.

12. The backlight module according to claim 11, characterized in that, The light source is disposed on the near-incident light side of the optical film, and the near-incident light side is connected to the abutting side, and the near-incident light side is closer to the light source than the abutting side.

13. The backlight module according to claim 11, characterized in that, Each of the aforementioned abutting portions is located at a corner of the main body, and the corner of the frame is a non-recessed planar structure.

14. The backlight module according to claim 11, characterized in that, A first gap is formed between the main body and the planar inner wall, and a second gap is formed between the outer side of each abutting part and the planar inner wall, the second gap being smaller than the first gap.

15. A display device, characterized in that, Include: The backlight module according to any one of claims 8 to 14; and The display panel is located on one side of the backlight module.

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