Optical composite film, backlight module and liquid crystal display equipment

Abstract

The utility model relates to an optical composite film, a backlight module and liquid crystal display equipment. The optical composite film includes: a first substrate layer; the brightness enhancement film layer is connected with one side, in the first direction, of the first base material layer, and the brightness enhancement film layer is used for enhancing the brightness of light rays emitted to the first base material layer from the brightness enhancement film layer in the direction perpendicular to the second direction; the sight-expanding cornea layer is connected with the side, back on to the brightness enhancement film layer, of the brightness enhancement film layer in the first direction, and the sight-expanding cornea layer comprises a plurality of inverse prisms which are sequentially connected in the third direction; and the inverse prism is gradually narrowed along the direction of the sight-expanding cornea layer close to the first substrate layer. Therefore, the light brightness of a viewer at a 0-degree viewing angle in the horizontal direction, a viewing angle near the 0-degree viewing angle and viewing angles with different inclination degrees in the left-right direction can be comprehensively ensured as much as possible, and the viewing effect at a large viewing angle is improved.

Description

Technical Field

[0001] This application relates to the field of optical composite film technology, and in particular to optical composite films, backlight modules, and liquid crystal display devices. Background Technology

[0002] As people's demands for the optical performance of LCD display devices such as monitors, televisions, and interactive smart panels increase, it has spurred the development of more new technologies. In many scenarios, we need to observe LCD display devices from different angles. For example, when students in a classroom view an LCD display, the students in the middle row have a 0-degree viewing angle, directly facing the display. The viewing angles increase as students move from the middle to the left and right, reaching up to 60 degrees for students at the edges. Typically, the brightness of an LCD display varies depending on the viewing angle. Brightness is highest at a 0-degree viewing angle, but at a 60-degree viewing angle, the brightness is often less than 20% of that at a 0-degree viewing angle. This can result in students at the edges having difficulty seeing the displayed content, leading to a poor viewing experience.

[0003] It is evident that liquid crystal display devices in related technologies have low brightness and poor viewing experience at wide viewing angles. Utility Model Content

[0004] Therefore, it is necessary to provide an optical composite film, a backlight module, and a liquid crystal display device to address the problem of low brightness and poor viewing effect of display devices in related technologies at wide viewing angles.

[0005] An optical composite film, the optical composite film comprising:

[0006] First substrate layer;

[0007] A brightness enhancement film layer is connected to one side of the first substrate layer along a first direction. The brightness enhancement film layer is used to enhance the brightness of light emitted from the brightness enhancement film layer to the first substrate layer in a direction perpendicular to a second direction.

[0008] An expanding viewing angle film layer is connected to a side facing away from the brightening film layer along a first direction. The expanding viewing angle film layer includes a plurality of reverse prisms connected sequentially along a third direction. The reverse prisms gradually narrow along the direction of the expanding viewing angle film layer near the first substrate layer.

[0009] Wherein, the first direction, the second direction, and the third direction are perpendicular to each other.

[0010] When the aforementioned optical composite film is applied in a liquid crystal display device, light from the light source passes sequentially through the brightness enhancement film layer, the first substrate layer, and the viewing angle expansion film layer, thus becoming visible to the viewer. The brightness enhancement film layer enhances the brightness of light incident from the brightness enhancement film layer onto the first substrate layer in the horizontal direction, thereby improving the display brightness when the viewer views the screen horizontally. Because the reverse prism gradually narrows along the direction of the viewing angle expansion film layer towards the first substrate layer—that is, the distance between the first and second opposing sides of the reverse prism gradually decreases along a third direction—the reverse prism 510 refracts the light to the left and right when it enters the first and second sides of the reverse prism through the first substrate layer, causing the light to tilt to the left and right, thereby enhancing the brightness of the light in the leftward and rightward tilted directions. The tilt of the primary refracted light generated by the viewing angle expansion film layer is relatively small, and part of the primary refracted light remains close to the first direction, thus still ensuring the brightness of the light in the 0-degree viewing angle and the viewing angle range near 0 degrees. In this way, the light brightness can be guaranteed as comprehensively as possible for viewers at 0 degrees and near 0 degrees in the horizontal direction, as well as at different tilting angles to the left and right, thus improving the viewing effect at wide angles.

[0011] In one embodiment, the optical composite film further includes a second substrate layer, and the brightness enhancement film layer is disposed on the surface of the second substrate layer near the first substrate layer. The second substrate layer serves as a carrier for the brightness enhancement film layer, facilitating the fabrication of the brightness enhancement film layer.

[0012] In one embodiment, the brightness enhancement film layer includes a plurality of prisms sequentially connected along a second direction; the prisms gradually narrow along the direction of the brightness enhancement film layer near the first substrate layer. The prisms can converge incident light from the light source in the horizontal direction, enhancing the brightness of the light in the horizontal direction. Furthermore, they can reflect some light back to the direction of the light source, thereby allowing the light to be reused and further enhancing the brightness of the light in the horizontal direction.

[0013] In one embodiment, the optical composite film further includes a third substrate layer, and the viewing angle-expanding film layer is disposed on the surface of the third substrate layer near the first substrate layer. The third substrate layer serves as a carrier for the viewing angle-expanding film layer, facilitating its fabrication.

[0014] In one embodiment, the optical composite film further includes a diffusion layer disposed on the side of the third substrate layer opposite to the wide-view film layer, the diffusion layer including an optical adhesive and a plurality of diffusion particles dispersed in the optical adhesive.

[0015] After passing through the viewing angle widening film layer and the third substrate layer, light enters the diffusion layer. The diffusion layer refracts the light again, causing it to diverge in all directions, thus achieving uniform light distribution and improving the problem of uneven brightness at different viewing angles.

[0016] In one embodiment, the cross-sectional shape of the reverse prism is an isosceles triangle, with the apex of the isosceles triangle facing the first substrate layer.

[0017] In this way, the first and second sides are tilted at the same degree, which allows the light refracted by the widening film layer to be distributed as evenly as possible from left to right, and the tilting degree from left to right to be as equal as possible.

[0018] In one embodiment, the height of the isosceles triangle is greater than or equal to 30 μm and less than or equal to 70 μm; the vertex angle of the isosceles triangle is greater than or equal to 30° and less than or equal to 70°.

[0019] Within this height and apex angle range, the first and second sides can be positioned at a suitable tilt angle, thereby ensuring that the light refracted by the widening film layer can comprehensively guarantee the light brightness for the viewer at a horizontal viewing angle of 0 degrees and near 0 degrees, as well as at different tilt angles to the left and right.

[0020] In one embodiment, the reverse prism has a first side surface, a first bottom surface, a second side surface, and a second bottom surface connected end to end; the first bottom surface and the second bottom surface are opposite to each other along the first direction, and the first bottom surface faces the first substrate layer; the first side surface and the second side surface are opposite to each other along the third direction;

[0021] The angle between the first side surface and the second bottom surface is equal to the angle between the second side surface and the second bottom surface.

[0022] After light is emitted from the brightness enhancement film layer, when the incident light rays that pass through the first substrate layer and are directed toward the widening film layer pass through the first bottom surface, the incident light rays pass through the first bottom surface along the original incident direction, or the refraction angle of the first bottom surface on the incident light rays is small, thereby enabling more light rays to pass through the reverse prism along the 0-degree viewing angle and near the 0-degree viewing angle. In turn, while enhancing the brightness of light rays tilted to the left and right after passing through the first side and the second side, the brightness of light rays at the 0-degree viewing angle and near the 0-degree viewing angle is further guaranteed.

[0023] In one embodiment, the vertical distance from the end of the first side away from the second bottom surface to the second bottom surface is greater than or equal to 15 μm and less than or equal to 60 μm;

[0024] The acute angle between the virtual extension surface of the first side and the virtual extension surface of the second side is greater than or equal to 30° and less than or equal to 70°.

[0025] Within this height and angle range, the first and second sides can be positioned at a suitable tilt angle, thereby ensuring that the light refracted by the widening film layer can comprehensively guarantee the brightness of the light for the viewer at a horizontal viewing angle of 0 degrees and near 0 degrees, as well as at different tilt angles to the left and right.

[0026] In one embodiment, the first bottom surface is a plane. When incident light rays from the first substrate layer toward the widening-view film layer pass through the first bottom surface, they pass through the first bottom surface along the original incident direction, thereby enabling more light rays to pass through the reverse prism at a 0-degree viewing angle.

[0027] In one embodiment, the first bottom surface is a convex arc surface, and the height of the convex arc surface protruding from the first side surface and the second side surface is greater than or equal to 1 μm and less than or equal to 12 μm.

[0028] When incident light rays from the first substrate layer to the widening-view film layer pass through the first bottom surface, part of the incident light rays pass through the first bottom surface along the original incident direction, while the other part of the incident light rays become first-fold refracted light. Since the height of the convex arc surface protruding from the first and second side surfaces is greater than or equal to 1 μm and less than or equal to 12 μm, the degree of protrusion is small. Therefore, it can be ensured that the refraction angle of the first-fold refracted light is small, thereby allowing more light rays to pass through the reverse prism along and near the 0-degree viewing angle.

[0029] In one embodiment, the first bottom surface is a concave arc surface, and the concave arc surface has a depth greater than or equal to 1 μm and less than or equal to 12 μm.

[0030] When incident light rays from the first substrate layer to the widening-view film layer pass through the first bottom surface, part of the incident light rays pass through the first bottom surface along the original incident direction, while the other part of the incident light rays become first-fold refracted light. Since the concave depth of the concave arc surface is greater than or equal to 1μm and less than or equal to 12μm, the degree of concavity is relatively small. Therefore, it can be ensured that the refraction angle of the first-fold refracted light is small, thereby allowing more light rays to pass through the reverse prism along and near the 0-degree viewing angle.

[0031] In one embodiment, the brightness enhancement film layer is bonded to the first substrate layer via a first optical adhesive layer; the viewing angle widening film layer is bonded to the first substrate layer via a second optical adhesive layer. Thus, the viewing angle widening film layer and the brightness enhancement film layer are bonded together via the first substrate layer. Furthermore, light from the brightness enhancement film layer can pass through the first optical adhesive layer and reach the first substrate layer. Light from the first substrate layer can pass through the second optical adhesive layer and reach the viewing angle widening film layer.

[0032] A backlight module includes a backplate and a light source disposed on the backplate, and an optical composite film as described in any of the above embodiments, wherein the brightness enhancement film layer is located on the side of the widening viewing angle film layer closer to the light source.

[0033] A liquid crystal display device includes the backlight module described in the above embodiments. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of an optical composite film according to one embodiment.

[0035] Figure 2 for Figure 1 The structure explodes.

[0036] Figure 3 This is a partially enlarged view of the connection structure between the third substrate layer and the wide-view film layer in one embodiment.

[0037] Figure 4 This is a schematic diagram of the connection structure between the second substrate layer and the brightness enhancement film layer in one embodiment.

[0038] Figure 5 for Figure 4 A magnified view of region A in the image.

[0039] Figure 6 This is a partially enlarged view of the connection structure between the third substrate layer and the wide-view film layer in another embodiment.

[0040] Figure 7 This is a partially enlarged view of the connection structure between the third substrate layer and the wide-view film layer in another embodiment.

[0041] Figure 8 This is a partially enlarged view of the connection structure between the third substrate layer and the wide-view film layer in another embodiment.

[0042] Explanation of reference numerals in the attached figures:

[0043] ZZ', First direction; XX', Second direction; YY', Third direction;

[0044] 100. First substrate layer; 110. First optical adhesive layer; 120. Second optical adhesive layer;

[0045] 200. Second substrate layer;

[0046] 300, Brightening film layer; 310, Prism; 311, First surface; 312, Second surface;

[0047] 400, Third substrate layer;

[0048] 500. Widening viewing angle film layer; 510. Reverse prism; 511. First side surface; 512. Second side surface; 513. First bottom surface; 514. Second bottom surface;

[0049] 600. Diffusion layer. Detailed Implementation

[0050] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0051] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0052] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0053] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0054] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0055] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0056] In liquid crystal display devices of related technologies, the optical composite film generally includes a first brightness enhancement film and a second brightness enhancement film stacked along the thickness direction (perpendicular to the display surface). The first brightness enhancement film includes multiple prisms connected sequentially in the vertical direction, and the second brightness enhancement film includes multiple prisms connected sequentially in the horizontal direction. The multiple prisms of the first brightness enhancement film are used to converge and focus upward and downward tilted light to the horizontal direction, thereby adapting to the viewer's horizontal viewing angle and achieving the effect of brightness enhancement. The viewing angle of a viewer when viewing a liquid crystal display device is usually horizontal (horizontal straight view, i.e., 0-degree viewing angle, or horizontally tilted to the left, or horizontally tilted to the right), and they do not view upward or downward. Therefore, converging and focusing upward and downward tilted light to the horizontal direction will not affect the viewer's viewing angle. The second brightness enhancement film has multiple prisms used to converge and focus light rays tilted to the left and right into a direction perpendicular to the display surface. This results in the highest brightness when the viewer looks directly at the LCD device at a horizontal angle (0 degrees). The brightness of the LCD device decreases when the viewing angle is tilted to the left or right, and the greater the tilt, the lower the brightness and the worse the viewing effect. Consequently, the LCD device has low brightness and poor viewing effect at large viewing angles. To address this, this application provides an optical composite film, a backlight module, and an LCD device. The optical composite film includes a first substrate layer 100, a brightness enhancement film layer 300, and a viewing angle widening film layer 500. After light is emitted from the brightness enhancement film layer 300, it passes through the first substrate layer 100 and reaches the viewing angle widening film layer 500. The viewing angle widening film layer 500 can refract the incident light rays into primary refracted light L22 and secondary refracted light L23 tilted to the left and right, respectively, thereby enhancing the brightness of the light rays tilted to the left and right. Furthermore, because the primary refracted light L22 and the secondary refracted light L23 have different tilt angles, the light intensity can be enhanced across different tilt angles in the left and right directions. The primary refracted light L22 has a relatively smaller tilt angle; therefore, some light rays in the primary refracted light L22 remain close to the first direction ZZ', thus ensuring light brightness at and around a 0-degree viewing angle. In this way, the light brightness can be comprehensively guaranteed for the viewer at a horizontal viewing angle near 0 degrees and at different tilt angles in the left and right directions.

[0057] Please refer to Figure 1 and Figure 2 An embodiment of this application provides an optical composite film comprising a first substrate layer 100, a brightness enhancement film layer 300, and a viewing angle widening film layer 500. For ease of explanation, the orientations are described using a first direction ZZ', a second direction XX', and a third direction YY'. The first direction ZZ', the second direction XX', and the third direction YY' are mutually perpendicular. In actual use of the optical composite film, the second direction XX' is vertical, the first direction ZZ' is horizontal and perpendicular to the display surface, and the third direction YY' is horizontal in a left-right direction.

[0058] The brightness enhancement film layer 300 is connected to the first substrate layer 100 along one side of the first direction ZZ'. The brightness enhancement film layer 300 is used to enhance the brightness of light incident from the brightness enhancement film layer 300 onto the first substrate layer 100 in a direction perpendicular to the second direction XX'. Specifically, the direction perpendicular to the second direction XX', i.e., the horizontal direction, can be along the first direction ZZ', or it can be a direction that is horizontal and inclined to the first direction ZZ'. By enhancing the brightness of light incident from the brightness enhancement film layer 300 onto the first substrate layer 100 in the horizontal direction, the display brightness is improved when the viewer views the display screen in a horizontal direction.

[0059] The widening-view film layer 500 is connected to the first substrate layer 100 along the first direction ZZ' on the side opposite to the brightness enhancement film layer 300. The widening-view film layer 500 includes a plurality of reverse prisms 510 connected sequentially along the third direction YY'. The reverse prisms 510 gradually narrow along the direction of the widening-view film layer 500 near the first substrate layer 100. The first substrate layer 100 is used to connect the brightness enhancement film layer 300 and the widening-view film layer 500, serving as the connection carrier between the two.

[0060] Please refer to Figure 3 The reverse prism 510 has a first side surface 511 and a second side surface 512 arranged opposite to each other along a third direction YY'. Along the direction of the wide-view film layer 500 near the first substrate layer 100, the reverse prism 510 gradually narrows, that is, the distance between the first side surface 511 and the second side surface 512 gradually decreases.

[0061] After light is emitted from the brightness enhancement film layer 300, the incident light L21, which passes through the first substrate layer 100 and is projected onto the first side surface 511, forms primary refracted light L22 through refraction at the first side surface 511. The remaining light is reflected from the first side surface 511 onto the second side surface 512 of the adjacent reverse prism 510, and then refracted again by the second side surface 512 to form secondary refracted light L23. The tilt direction of the secondary refracted light L23 is opposite to that of the primary refracted light L22, and the tilt degree of the secondary refracted light L23 is greater than that of the primary refracted light L22. Similarly, when light is emitted from the brightness enhancement film layer 300 and the incident light L21, which passes through the first substrate layer 100 and is projected onto the second side surface 512, primary and secondary refracted light with opposite tilt directions and different tilt degrees can also be formed.

[0062] Therefore, when light emitted from the brightness enhancement film layer 300 passes through the first substrate layer 100 and strikes the viewing angle expansion film layer 500, the viewing angle expansion film layer 500 refracts the incident light into primary refracted light L22 and secondary refracted light L23 tilted to the left and right, respectively, thereby enhancing the brightness of the light in the left and right tilted directions. Furthermore, since the primary refracted light L22 and secondary refracted light L23 have different tilt angles, the light intensity of different tilted viewing angles in the left and right directions can be enhanced. The tilt angle of the primary refracted light L22 is relatively small; therefore, some light in the primary refracted light L22 remains close to the first direction ZZ', thus still ensuring the brightness of the light in the 0-degree viewing angle and the viewing angle range near 0 degrees. In this way, the brightness of the light can be guaranteed as comprehensively as possible for the viewer at a horizontal viewing angle near 0 degrees and at different tilted viewing angles in the left and right directions.

[0063] exist Figure 3 In the embodiment shown, the first side 511 and the second side 512 intersect, so that the cross-section of the reverse prism 510 is triangular.

[0064] When the aforementioned optical composite film is applied in a liquid crystal display device, light from the light source passes sequentially through the brightness enhancement film layer 300, the first substrate layer 100, and the viewing angle expansion film layer 500, thus becoming visible to the viewer. The brightness enhancement film layer 300 enhances the brightness of light incident from the brightness enhancement film layer 300 onto the first substrate layer 100 in the horizontal direction, thereby improving the display brightness when the viewer views the screen horizontally. Since the reverse prism 510 gradually narrows along the direction of the viewing angle expansion film layer 500 towards the first substrate layer 100, that is, the distance between the opposing first side surface 511 and second side surface 512 of the reverse prism 510 along the third direction YY' gradually decreases, when light passes through the first substrate layer 100 and enters the first side surface 511 and second side surface 512 of the reverse prism 510, the reverse prism 510 refracts the light to the left and right, causing the light to tilt to the left and right, thereby enhancing the brightness of the light in the left and right tilted directions. Among them, the tilt of the primary refracted light L22 generated by the widening-view film layer 500 is relatively small. Some of the light rays in the primary refracted light L22 are still close to the first direction ZZ', thus ensuring the brightness of the light in the 0-degree viewing angle and the viewing angle range near 0 degrees. In this way, the brightness of the light can be guaranteed as comprehensively as possible for the viewer at the 0-degree viewing angle and the viewing angle near 0 degrees in the horizontal direction, as well as at different tilt angles to the left and right, thus improving the viewing effect at wide viewing angles.

[0065] Please combine Figure 1 and Figure 2In one embodiment, the optical composite film further includes a second substrate layer 200, and a brightness enhancement film layer 300 is disposed on the surface of the second substrate layer 200 near the first substrate layer 100. The second substrate layer 200 is located on the side of the first substrate layer 100 along the first direction ZZ'. The second substrate layer 200 serves as a carrier for the brightness enhancement film layer 300, facilitating the fabrication of the brightness enhancement film layer 300.

[0066] Please combine Figure 1 and Figure 2 In one embodiment, the optical composite film further includes a third substrate layer 400, and a brightness enhancement film layer 300 is disposed on the surface of the third substrate layer 400 near the first substrate layer 100. The third substrate layer 400 is located on the side of the first substrate layer 100 along the first direction ZZ'. The third substrate layer 400 serves as a carrier for the widening viewing angle film layer 500, facilitating the fabrication of the widening viewing angle film layer 500.

[0067] Please refer to Figure 4 In one embodiment, the brightness enhancement film layer 300 includes a plurality of prisms 310 sequentially connected along a second direction XX'. The prisms 310 gradually narrow along the direction of the brightness enhancement film layer 300 near the first substrate layer 100.

[0068] Please combine Figure 4 and Figure 5 The prism 310 has a first surface 311 and a second surface 312 that are opposite to each other along the second direction XX'. Along the direction of the brightening film layer 300 near the first substrate layer 100, the prism 310 gradually narrows, that is, the distance between the first surface 311 and the second surface 312 gradually decreases.

[0069] like Figure 5 As shown, when incident light L11 from the light source enters the brightness enhancement film 300 and passes through the first surface 311 of the brightness enhancement film 300, part of the light is refracted by the first surface 311 to form primary refracted light L12; the other part of the light does not pass through the first surface 311 and is reflected towards the second surface 312. The primary refracted light L12 converges horizontally relative to the incident light L11, thus enhancing the brightness of the light in the horizontal direction. Of the light reflected towards the second surface 312, some light is lost due to refraction by the second surface 312, and some does not pass through the second surface 312 but is reflected back to the light source, i.e., total internal reflection light L13. Thus, the total internal reflection light L13 can be reused, further enhancing the brightness of the light in the horizontal direction. Similarly, when incident light L11 from the light source enters the brightness enhancement film 300 and passes through the second surface 312 of the brightness enhancement film 300, the light can also converge horizontally, enhancing the brightness of the light in the horizontal direction. It can be seen that the brightness enhancement film 300 can converge the incident light L11 from the light source into the brightness enhancement film 300 in the horizontal direction, thereby enhancing the brightness of the light in the horizontal direction.

[0070] exist Figure 5 In the illustrated embodiment, the first surface 311 and the second surface 312 intersect, resulting in a triangular cross-section for the prism 310. Optionally, the cross-section of the prism 310 is an isosceles triangle, with the apex of the isosceles triangle facing the first substrate layer 100.

[0071] In other embodiments, the prism 310 may also be of other shapes, such as a trapezoidal cross-section, and there is no limitation thereto.

[0072] Optionally, the material of the first substrate layer 100 is selected from any one of polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), polyethylene (PE), and polymethyl methacrylate (PMMA).

[0073] Optionally, the thickness of the first substrate layer 100 is greater than or equal to 100 μm and less than or equal to 300 μm.

[0074] Optionally, the material of the second substrate layer 200 is selected from any one of polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), polyethylene (PE), and polymethyl methacrylate (PMMA).

[0075] Optionally, the material of the third substrate layer 400 is selected from any one of polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), polyethylene (PE), and polymethyl methacrylate (PMMA).

[0076] Optionally, the prism 310 can be prepared by pressing UV adhesive onto the surface of the second substrate layer 200 using a roller mold, and then curing it by UV lamp irradiation.

[0077] Optionally, the reverse prism 510 can be prepared by pressing UV adhesive onto the surface of the third substrate layer 400 using a roller mold, and then curing it by UV lamp irradiation.

[0078] After being refracted by the 500° viewing angle widening film, the light rays are directed in different directions of tilt. Therefore, the perceived brightness of the LCD display will vary depending on the viewing angle. To prevent uneven brightness caused by large differences in brightness across different viewing angles, please refer to... Figure 1 and Figure 2 In one embodiment, the optical composite film further includes a diffusion layer 600, which is disposed on the side of the third substrate layer 400 opposite to the viewing angle film layer 500. The diffusion layer 600 includes an optical adhesive and a plurality of diffusion particles dispersed in the optical adhesive.

[0079] After passing through the widening film layer 500 and the third substrate layer 400, the light enters the diffusion layer 600. The diffusion layer 600 refracts the light again, causing it to diverge in all directions, thereby achieving uniform light distribution and improving the problem of uneven brightness at different viewing angles.

[0080] Optionally, the diffusion layer 600 can be prepared by coating an optical adhesive containing multiple diffusion particles onto the surface of the third substrate layer 400, and after the optical adhesive cures, the diffusion layer 600 is formed.

[0081] Optionally, the optical adhesive of the diffusion layer 600 may be made of either polyurethane adhesive or epoxy resin, or a mixture of both.

[0082] Optionally, the multiple diffused particles are selected from either PMMA particles and PBMA particles or a mixture of both.

[0083] Optionally, the particle size of PMMA is greater than or equal to 1 μm and less than or equal to 50 μm. The particle size of PBMA is greater than or equal to 1 μm and less than or equal to 50 μm.

[0084] Optionally, the ratio of optical adhesive to diffusion particles is such that the weight of optical adhesive is 100 parts and the weight of diffusion particles is greater than or equal to 4 parts and less than or equal to 20 parts.

[0085] Please refer to Figure 3 In one embodiment, the cross-sectional shape of the reverse prism 510 is an isosceles triangle, with the apex of the isosceles triangle facing the first substrate layer 100.

[0086] Specifically, since the cross-sectional shape of the reverse prism 510 is an isosceles triangle, the first side 511 and the second side 512 are symmetrically arranged in the left and right directions, so that the light refracted by the widening-view film layer 500 can be distributed as evenly as possible from left to right and the left and right tilts are as similar as possible.

[0087] Please refer to Figure 3 In one embodiment, the height M of the isosceles triangle corresponding to the cross-section of the reverse prism 510 is greater than or equal to 30 μm and less than or equal to 70 μm. The apex angle of the isosceles triangle corresponding to the cross-section of the reverse prism 510 is greater than or equal to 30° and less than or equal to 70°. Within this height and apex angle range, the first side 511 and the second side 512 can be at a relatively suitable tilt angle, thereby ensuring that the light refracted by the widening-view film layer 500 can comprehensively guarantee the light brightness for the viewer at a horizontal viewing angle of 0 degrees and near 0 degrees, as well as at different tilt angles to the left and right.

[0088] Please refer to Figures 6 to 8In some embodiments, the reverse prism 510 has a first side surface 511, a first bottom surface 513, a second side surface 512, and a second bottom surface 514 connected end to end. The first bottom surface 513 and the second bottom surface 514 are opposite to each other along a first direction ZZ', and the first bottom surface 513 faces the first substrate layer 100. The first side surface 511 and the second side surface 512 are opposite to each other along a third direction YY'. The angle between the first side surface 511 and the second bottom surface 514 is equal to the angle between the second side surface 512 and the second bottom surface 514. In this way, the first side surface 511 and the second side surface 512 are symmetrically arranged in the left-right direction, so that the light refracted by the widening-view film layer 500 is distributed as evenly as possible from left to right, and the left and right tilts are as similar as possible.

[0089] Since the first bottom surface 513 faces the first substrate layer 100, when light rays emitted from the brightness enhancement film layer 300 pass through the first substrate layer 100 and are incident on the widening film layer 500, the incident light rays pass through the first bottom surface 513 along the original incident direction, or the first bottom surface 513 has a smaller refraction angle on the incident light rays. This allows more light rays to pass through the reverse prism 510 along the 0-degree viewing angle and near the 0-degree viewing angle. Furthermore, while enhancing the brightness of light rays tilted to the left and right after passing through the first side surface 511 and the second side surface 512, the brightness of light rays at the 0-degree viewing angle and near the 0-degree viewing angle is further guaranteed.

[0090] Please refer to Figures 6 to 8 In some embodiments, the vertical distance H from the end of the first side surface 511 (or the second side surface 512) away from the second bottom surface 514 to the second bottom surface 514 is greater than or equal to 15 μm and less than or equal to 60 μm. The acute angle α between the virtual extension surface of the first side surface 511 and the virtual extension surface of the second side surface 512 is greater than or equal to 30° and less than or equal to 70°. Within this height and angle range, the first side surface 511 and the second side surface 512 can be at a relatively suitable tilt angle, thereby ensuring that the light refracted by the widening viewing angle film layer 500 can comprehensively guarantee the light brightness for the viewer at a horizontal viewing angle of 0 degrees and near 0 degrees, as well as at different tilt angles to the left and right.

[0091] Please refer to Figure 6 In another embodiment, the first bottom surface 513 is a plane and parallel to the side of the first substrate layer 100 opposite to it. Thus, when the incident light L34, after being emitted from the brightness enhancement film layer 300 and passing through the first substrate layer 100 to the widening film layer 500, passes through the first bottom surface 513 along the original incident direction, it allows more light to pass through the reverse prism 510 at a 0-degree angle.

[0092] Please refer to Figure 7In another embodiment, the first bottom surface 513 is a convex arc surface. Thus, when the incident light L44, after exiting the brightness enhancement film layer 300 and passing through the first substrate layer 100 towards the widening angle film layer 500, passes through the first bottom surface 513, a portion of the incident light L44 passes through the first bottom surface 513 along its original incident direction, while the other portion of the incident light L44 becomes primary refracted light L45. Since the height D1 of the convex arc surface protruding from the first side surface 511 and the second side surface 512 is greater than or equal to 1 μm and less than or equal to 12 μm, the degree of protrusion is relatively small. Therefore, the refraction angle of the primary refracted light L45 can be kept small, allowing more light to pass through the reverse prism 510 along and near the 0-degree viewing angle.

[0093] Meanwhile, since the first bottom surface 513 is a convex arc surface, the convex arc surface can refract a part of the incident light L44 that was originally along the 0-degree angle to other angles, forming a first refracted light L45, which can fill the brightness of other angles and reduce the brightness difference between different angles, making the brightness of light from different angles more uniform.

[0094] Please refer to Figure 8 In another embodiment, the first bottom surface 513 is a concave arc surface. Thus, when the incident light L54, after exiting the brightness enhancement film layer 300 and passing through the first substrate layer 100 towards the widening angle film layer 500, passes through the first bottom surface 513, a portion of the incident light L54 passes through the first bottom surface 513 along its original incident direction, while the other portion of the incident light L54 becomes primary refracted light L55. Since the concave depth D2 of the concave arc surface is greater than or equal to 1 μm and less than or equal to 12 μm, the degree of concavity is relatively small. Therefore, the refraction angle of the primary refracted light L55 can be kept small, allowing more light to pass through the reverse prism 510 along and near the 0-degree viewing angle.

[0095] Meanwhile, since the first bottom surface 513 is a concave arc surface, the concave arc surface can refract a part of the incident light L54 that was originally along the 0-degree viewing angle to other angles, forming a first refracted light L55, which can fill the brightness of other viewing angles, and thus reduce the brightness difference of different viewing angles, making the brightness of light from different viewing angles more uniform.

[0096] In one embodiment, the brightness enhancement film layer 300 is bonded to the first substrate layer 100 via a first optical adhesive layer 110, and the viewing angle widening film layer 500 is bonded to the first substrate layer 100 via a second optical adhesive layer 120, thereby bonding the viewing angle widening film layer 500 and the brightness enhancement film layer 300 through the first substrate layer 100. Light from the brightness enhancement film layer 300 can pass through the first optical adhesive layer 110 and reach the first substrate layer 100. Light from the first substrate layer 100 can pass through the second optical adhesive layer 120 and reach the viewing angle widening film layer 500.

[0097] Optionally, the thickness of the first optical adhesive layer 110 is greater than or equal to 1 μm and less than or equal to 2 μm.

[0098] Optionally, the thickness of the second optical adhesive layer 120 is greater than or equal to 1 μm and less than or equal to 2 μm.

[0099] One embodiment of this application also provides a backlight module, including a backplate and a light source disposed on the backplate, as well as an optical composite film of any of the above embodiments, wherein the brightness enhancement film layer 300 is located on the side of the viewing angle expansion film layer 500 closer to the light source. Thus, the light from the light source passes sequentially through the brightness enhancement film layer 300 and the first substrate layer 100 before entering the viewing angle expansion film layer 500.

[0100] One embodiment of this application also provides a liquid crystal display device, including the backlight module of the above embodiment.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An optical composite film, characterized in that, The optical composite film includes: First substrate layer (100); A brightness enhancement film layer (300) is connected to one side of the first substrate layer (100) along the first direction (ZZ'). The brightness enhancement film layer (300) is used to enhance the brightness of light emitted from the brightness enhancement film layer (300) to the first substrate layer (100) in a direction perpendicular to the second direction (XX'). A widening-view film layer (500) is connected to a side facing away from the brightening film layer (300) along a first direction (ZZ'). The widening-view film layer (500) includes a plurality of reverse prisms (510) connected sequentially along a third direction (YY'). The reverse prisms (510) gradually narrow along the direction of the widening-view film layer (500) close to the first substrate layer (100). Among them, the first direction (ZZ'), the second direction (XX'), and the third direction (YY') are perpendicular to each other.

2. The optical composite film according to claim 1, characterized in that, The optical composite film further includes a second substrate layer (200), and the brightness enhancement film layer (300) is disposed on the surface of the second substrate layer (200) on the side close to the first substrate layer (100).

3. The optical composite film according to claim 1, characterized in that, The brightness enhancement film layer (300) includes a plurality of prisms (310) connected sequentially along the second direction (XX'); the prisms (310) gradually narrow along the direction of the brightness enhancement film layer (300) close to the first substrate layer (100).

4. The optical composite film according to claim 1, characterized in that, The optical composite film further includes a third substrate layer (400), and the brightening film layer (300) is disposed on the surface of the third substrate layer (400) on the side close to the first substrate layer (100).

5. The optical composite film according to claim 4, characterized in that, It also includes a diffusion layer (600), which is disposed on the side of the third substrate layer (400) facing away from the wide-view film layer (500), and the diffusion layer (600) includes an optical adhesive and a plurality of diffusion particles dispersed in the optical adhesive.

6. The optical composite film according to claim 1, characterized in that, The cross-sectional shape of the reverse prism (510) is an isosceles triangle, with the apex of the isosceles triangle facing the first substrate layer (100).

7. The optical composite film according to claim 6, characterized in that, The height (M) of the isosceles triangle is greater than or equal to 30 μm and less than or equal to 70 μm; the vertex angle of the isosceles triangle is greater than or equal to 30° and less than or equal to 70°.

8. The optical composite film according to claim 1, characterized in that, The reverse prism (510) has a first side surface (511), a first bottom surface (513), a second side surface (512), and a second bottom surface (514) connected end to end in sequence; the first bottom surface (513) and the second bottom surface (514) are opposite to each other along the first direction (ZZ'), and the first bottom surface (513) faces the first substrate layer (100); the first side surface (511) and the second side surface (512) are opposite to each other along the third direction (YY'); The angle between the first side surface (511) and the second bottom surface (514) is equal to the angle between the second side surface (512) and the second bottom surface (514).

9. The optical composite film according to claim 8, characterized in that, The vertical distance (H) from the end of the first side surface (511) away from the second bottom surface (514) to the second bottom surface (514) is greater than or equal to 15 μm and less than or equal to 60 μm; The acute angle (α) between the virtual extension surface of the first side (511) and the virtual extension surface of the second side (512) is greater than or equal to 30° and less than or equal to 70°.

10. The optical composite film according to claim 8, characterized in that, The first bottom surface (513) is a plane; Alternatively, the first bottom surface (513) is a convex arc surface, and the height (D1) of the convex arc surface protruding from the first side surface (511) and the second side surface (512) is greater than or equal to 1 μm and less than or equal to 12 μm; Alternatively, the first bottom surface (513) is a concave arc surface, wherein the concave depth (D2) of the concave arc surface is greater than or equal to 1 μm and less than or equal to 12 μm.

11. The optical composite film according to claim 1, characterized in that, The brightening film layer (300) is bonded to the first substrate layer (100) by a first optical adhesive layer (110); the widening film layer (500) is bonded to the first substrate layer (100) by a second optical adhesive layer (120).

12. A backlight module, characterized in that, The device includes a back plate and a light source disposed on the back plate, and an optical composite film according to any one of claims 1 to 11, wherein the brightness enhancement film layer (300) is located on the side of the widening viewing angle film layer (500) closer to the light source.

13. A liquid crystal display device, characterized in that, Includes the backlight module as described in claim 12.

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