Optical film structure, backlight module and display device

Abstract

This utility model relates to an optical film structure, a backlight module, and a display device. The optical film structure has opposing first and second surfaces, and includes a plurality of first prisms and a plurality of second prisms. These first prisms are located on the first surface, each extending along a first direction. These second prisms are located on the second surface, each extending along a second direction different from the first direction. These second prisms have an arrangement density y, and each second prism has interconnected first and second inclined planes, with an angle x between the first and second inclined planes. The arrangement density y and the angle x satisfy the first density mathematical formula: 0 < y ≤ -0.00000543x. 3 +0.00193x 2 -0.20997x + 7.46116.

Description

[0001] This application claims priority to Chinese Patent Application No. 202520906619.2, filed on May 9, 2025, entitled "Optical Film Structure, Backlight Module and Display Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to an optical film structure, a backlight module including the aforementioned optical film structure, and a display device including the aforementioned backlight module. Background Technology

[0003] TCO certification is a display device certification standard promoted by the Swedish Federation of Professional Employees. It sets standards for human health and the ecological environment, directly related to the impact of display devices on user health. For example, to improve user comfort and reduce fatigue, TCO certification has certain requirements for the ergonomic characteristics of display devices, such as brightness uniformity specifications at different viewing angles.

[0004] Currently, the optical films used in backlight modules are mainly used to concentrate light at a positive angle. However, most brightness enhancement films on the market today can only converge light from a single dimension. To simultaneously enhance brightness in another dimension, another brightness enhancement film with different directional properties needs to be superimposed. This superposition method not only increases manufacturing costs and complexity but also has the following significant drawbacks:

[0005] Limited viewing angle: Although traditional brightness enhancement films can improve brightness, they are often accompanied by a narrowing of the viewing angle. When users view the screen from an angle other than directly, the brightness and color performance of the image will be greatly reduced.

[0006] The addition of multiple layers of film increases thickness and cost: The design of double-layer brightness enhancement film inevitably increases the overall thickness and manufacturing cost of the display device, which is not conducive to the trend of thinner and lighter design.

[0007] Therefore, developing an optical film structure that can achieve uniform brightness across different viewing angles when applied to display devices, and improve the contrast of the viewing angle range for normal use, is one of the goals that those skilled in the art wish to achieve. Utility Model Content

[0008] The purpose of this utility model is to provide an optical film structure, a backlight module including the aforementioned optical film structure, and a display device including the aforementioned backlight module. By designing the arrangement density and included angle of the prisms in the optical film structure, the display device can achieve uniform brightness at different viewing angles and improve the contrast of the viewing angle range during normal use.

[0009] The present invention provides an optical film structure in at least one embodiment, having opposing first and second surfaces, and comprising a plurality of first prisms and a plurality of second prisms. The first prisms are located on the first surface, each extending along a first direction. The second prisms are located on the second surface, each extending along a second direction different from the first direction. The second prisms have an arrangement density y, and each second prism has interconnected first and second inclined planes, with an angle x between the first and second inclined planes. The arrangement density y and the angle x satisfy a first density mathematical formula, where the first density mathematical formula is 0 < y ≤ -0.00000543x. 3 +0.00193x 2 -0.20997x+7.46116.

[0010] A backlight module according to at least another embodiment of this utility model includes a light guide plate, a light source, and the optical film structure. The light guide plate has a light-incident surface and a light-exit surface, the light source is disposed on the light-incident surface, and the optical film structure is disposed in front of the light-exit surface.

[0011] At least one other embodiment of this utility model provides a backlight module comprising a light source and the aforementioned optical film structure. The light source comprises a substrate and a plurality of light-emitting units arranged on the substrate, and the optical film structure is disposed in front of the light source.

[0012] A display device according to at least another embodiment of the present invention includes the backlight module and a display panel. The display panel is disposed in front of the backlight module. Attached Figure Description

[0013] Figure 1 This is a cross-sectional schematic diagram of the optical film structure of at least one embodiment of the present invention.

[0014] Figure 2 This is a graph of the first density mathematical formula of at least one embodiment of the present invention.

[0015] Figure 3 yes Figure 1 A magnified view of region A in the middle.

[0016] Figure 4 and Figure 5This is a graph showing the relationship between viewing angle and relative brightness simulated using the optical film structure of at least one embodiment of the present invention and the optical film structure of a comparative example.

[0017] Figure 6 This is a graph of the first density mathematical formula, the second density mathematical formula, and the third density mathematical formula of at least one embodiment of this utility model.

[0018] Figure 7 This is a graph showing the relationship between viewing angle and relative brightness simulated using the optical film structure of at least one embodiment of the present invention and the optical film structure of a comparative example.

[0019] Figures 8A to 8C These are schematic diagrams showing the output brightness from various angles simulated using the optical film structure of at least one embodiment of this utility model.

[0020] Figure 9A and Figure 9B These are schematic diagrams of a display device using an optical film structure according to at least one embodiment of the present invention.

[0021] Figure 10 This is a cross-sectional schematic diagram of the optical film structure of at least another embodiment of the present invention.

[0022] Figure 11 This is a cross-sectional schematic diagram of at least one embodiment of the backlight module of this utility model.

[0023] Figure 12 This is a cross-sectional schematic diagram of at least another embodiment of the backlight module of this utility model.

[0024] Figure 13 This is a cross-sectional schematic diagram of a display device according to at least one embodiment of the present invention. Detailed Implementation

[0025] In the following description, to clearly present the technical features of this utility model, the dimensions (e.g., length, width, thickness, and depth) of the elements (e.g., layers, films, substrates, and regions) in the accompanying drawings will be enlarged proportionally, and the number of some elements may be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of elements in the drawings and the size and shape of the elements, but should cover the dimensions, shapes, and deviations from both caused by actual manufacturing processes and / or tolerances.

[0026] Secondly, the terms "approximately," "approximately," or "substantially" used in this invention not only cover explicitly stated numerical values ​​and ranges, but also the permissible deviation range understood by those skilled in the art. This deviation range can be determined by errors generated during measurement, which may arise from limitations of the measurement system or process conditions. For example, two objects (e.g., planes or traces of a substrate) are "substantially parallel" or "substantially perpendicular," where "substantially parallel" and "substantially perpendicular" respectively represent that the parallelism and perpendicularity between the two objects can include non-parallelism and non-perpendicularity caused by permissible deviation ranges.

[0027] Furthermore, "approximately" can indicate that the value is within one or more standard deviations, such as ±30%, ±20%, ±10%, or ±5%. The use of terms such as "approximately," "approximately," or "substantially" in this invention allows for the selection of an acceptable range of deviations or standard deviations based on optical, etching, mechanical, or other properties, and does not apply to all optical, etching, mechanical, and other properties using a single standard deviation.

[0028] The spatial relative terms used in this invention, such as "below," "under," "above," and "above," are for the convenience of describing the relative relationship between one element or feature and another, as illustrated in the figures. The true meaning of these spatial relative terms includes other orientations. For example, when the illustration is rotated 180 degrees vertically, the relationship between one element and another may change from "below" or "under" to "above" or "above." Furthermore, the spatial relative descriptions used in this invention should be interpreted in the same way.

[0029] It should be understood that although the present invention may use terms such as "first," "second," and "third" to describe various elements or features, these elements or features should not be limited by these terms. These terms are primarily used to distinguish one element from another, or one feature from another. Furthermore, the term "or" as used in the present invention may, as appropriate, include any combination of one or more of the associated listed items.

[0030] Please see Figure 1 and Figure 2The optical film structure 100 has opposing first surfaces S1 and second surfaces S2, and includes a plurality of first prisms 102 and a plurality of second prisms 104. The first prisms 102 are located on the first surface S1, each extending along a first direction D1. The second prisms 104 are located on the second surface S2, each extending along a second direction D2 different from the first direction D1. Thus, when light enters the optical film structure 100 from either the first surface S1 or the second surface S2, the second prisms 104 can convert a portion of the perpendicular light into light in other directions, thereby causing the converted light to exit from the other of the first surface S1 and the second surface S2.

[0031] In detail, such as Figure 1 As shown, when light enters the optical film structure 100, some light rays (e.g., light ray L1) can directly pass through the blank area between adjacent second prisms 104 to produce frontal light output brightness along the frontal viewing direction, while some light rays (e.g., light ray L2) can be turned by the second prism 104 and output along the side viewing direction to produce side viewing brightness. The frontal viewing direction referred to here is the direction in which the light rays are parallel to the normal of the optical film structure 100 (i.e., the third direction D3), while there is an angle θ between the side viewing direction and the frontal viewing direction.

[0032] These second prisms 104 have an arrangement density y, and each second prism 104 has a first inclined plane C1 and a second inclined plane C2 connected to each other, with an angle x between the first inclined plane C1 and the second inclined plane C2. The arrangement density y and the angle x satisfy a first density mathematical expression, which is 0 < y ≤ -0.00000543x. 3 +0.00193x 2 -0.20997x+7.46116. By adjusting the arrangement density y and included angle x of the second prism 104, and by setting a polynomial calculation with y less than x, the ratio of light emitted from the front view to the side view can be further controlled, maintaining the brightness at the front viewing angle, reducing light leakage at large viewing angles, and thus improving display quality. In short, this invention mainly solves the problem of light leakage at large viewing angles. When the screen darkens, light can still be seen from the side view, causing poor contrast. Therefore, if light leakage at large viewing angles can be reduced, high contrast can be maintained.

[0033] Please see Figure 3 Each pair of adjacent second prisms 104 has a spacer 106 between them, and the aforementioned arrangement density y is calculated using a function, wherein the aforementioned function is... P is the distance between any two adjacent second prisms 104, and W is the width W of each gap 106. This function allows for precise control of the arrangement density of the second prisms 104, thereby achieving better optical effects.

[0034] In this embodiment, each second prism 104 is a strip-shaped groove, that is, a strip-shaped structure recessed along the direction from the second surface S2 to the first surface S1. In other embodiments, each second prism 104 may be a strip-shaped rib, that is, a strip-shaped structure protruding along the direction from the first surface S1 to the second surface S2. This structure is simple and easy to manufacture, which can reduce production costs. It should also be noted that when the second prism 104 is located on the light-incident side, it can be either recessed inward or protruding outward to achieve the beam-splitting effect. When the second prism 104 is located on the light-emitting side, it must be designed to be recessed inward to achieve the beam-splitting effect. If it is designed to be protruding outward, it will produce a light-focusing effect, which is not conducive to dispersing the light from the direct viewing direction to a slightly skewed viewing angle, and the viewing angle uniformity is still not good.

[0035] In some embodiments, the first direction D1 is substantially perpendicular to the second direction D2, and the first direction D1 and the second direction D2 are substantially perpendicular to the third direction D3. This vertical arrangement can not only effectively converge light sources in a single dimension, but also precisely control light sources in another dimension, effectively dispersing the light from the frontal direction to a slightly skewed viewing angle, thus improving the uniformity of the viewing angle.

[0036] In addition, this embodiment adopts a single-layer thin film structure, which effectively simplifies the manufacturing process, reduces costs, and facilitates the thinner and lighter design of the display device.

[0037] Please see Figure 4 Example 1 is an optical film structure with an included angle x of 90 degrees and an arrangement density y of 5% satisfying the first density mathematical formula; Example 2 is an optical film structure with an included angle x of 90 degrees and an arrangement density y of 10% satisfying the first density mathematical formula; the comparative example is an optical film that only has a prism that concentrates light out in a positive angle direction but does not have the aforementioned second prism 104, and the relative brightness is the result of normalization of the 0-degree light output brightness of the comparative example, Example 1, and Example 2. Figure 4 As can be seen, since the comparative example does not have the aforementioned second prism 104, it cannot generate side-view brightness by turning the light out along the side-view direction after the second prism 104 is turned. It can only allow the light to pass directly through the blank area and emit light from the front. Therefore, the relative brightness at 0 degrees (i.e., the front-view direction) is about 1, the relative brightness drops to about 0.95 at ±20 degrees, and the relative brightness drops to about 0.69 at ±40 degrees. The relative brightness of Example 1 and Example 2 at 0 degrees is about 0.93 and 0.91 respectively, the relative brightness drops to about 0.91 and 0.89 at ±20 degrees, and the relative brightness drops to about 0.7 at ±40 degrees.

[0038] Since the maximum value of the arrangement density y satisfying the first density mathematical formula is 23.84% when the included angle x of the second prism 104 is 90 degrees, when the arrangement density y is 5% and 10% respectively satisfying the first density mathematical formula, after the light enters the optical film structure 100, a portion of the light originally emitted from 0 degrees can be redirected by the second prism 104 to light emitted from other larger viewing angles. Therefore, as can be seen from the relative brightness decrease between 0 degrees and ±40 degrees in Examples 1 and 2, although the luminance at 0 degrees is weaker, decreasing by 2% at ±20 degrees compared to 0 degrees, the decrease at ±40 degrees is 21% and 19% compared to ±20 degrees, respectively, thus slowing down the luminance decrease at larger viewing angles. Compared to the comparative example's relative brightness decrease between 0 degrees and ±40 degrees, this device exhibits high luminance at a 0-degree viewing angle, a 5% decrease at ±20 degrees compared to 0 degrees, and a 26% decrease at ±40 degrees compared to ±20 degrees, indicating a rapid decrease in luminance at larger viewing angles. In other words, the design of the arrangement density y of the second prism 104 in the optical film structure 100, with the included angle x satisfying the first density mathematical formula, allows for a slower decrease in luminance at larger viewing angles. This improves the uniformity of brightness across different viewing angles, thus complying with the 5.10 Luminance uniformity-angular dependence specification of the Generation 9 (TCO) certification for displays.

[0039] Please see Figure 5 Example 3 is an optical film structure with an included angle x of 130 degrees and an arrangement density y of 50% satisfying the first density mathematical formula; Example 4 is an optical film structure with an included angle x of 120 degrees and an arrangement density y of 50% satisfying the first density mathematical formula; the comparative example is an optical film that only has a prism that concentrates light out in a positive angle direction but does not have the aforementioned second prism 104; and the relative brightness is the result of normalizing the front-view output brightness and side-view output brightness of the comparative example, Example 3, and Example 4. Figure 5 It can be seen that the comparative example has a relative brightness of about 1 at 0 degrees (i.e., the direct viewing direction), which decreases to about 0.95 at ±20 degrees and to about 0.02 at ±60 degrees. The relative brightness of Examples 3 and 4 is about 0.96 and 0.91 at 0 degrees, respectively, which decreases to about 0.78 and 0.79 at ±20 degrees and only to about 0.25 at ±60 degrees.

[0040] Since the included angles x of the second prism 104 are 120 degrees and 130 degrees respectively, when the included angles x increase from 90 degrees to 120 degrees and 130 degrees, the maximum value of the arrangement density y that satisfies the first density mathematical formula can also increase to 67.37% and 85.24%. Therefore, when the arrangement density y of 50% can satisfy the first density mathematical formula, after the light enters the optical film structure 100, a portion of the light, including but not limited to the original light emitted at ±40 degrees and ±20 degrees, can be redirected by the second prism 104 to light emitted within ±10 degrees. Therefore, compared with the comparative example, Embodiments 3 and 4 can highlight the local brightness within ±10 degrees, enhance the luminance and contrast near the positive viewing angle, and maintain the luminance within a ±40 degree angle, thus meeting the 5.10 brightness uniformity-angle dependence specification of the 9th generation TCO display certification.

[0041] It should also be noted that although the luminance of Examples 1 to 4 is relatively weak at a 0-degree viewing angle, in order to compensate for this problem, a high refractive index material (n≧1.59) can be used to make the second prism 104. Moreover, the higher the refractive index, the more the light concentration of ±20 degrees can be improved and concentrated towards the 0-degree viewing angle, which can effectively improve the brightness at the positive viewing angle.

[0042] Furthermore, after light enters the optical film structure 100, a portion of the light, including but not limited to light originally emanating at ±25 degrees and ±15 degrees, can be redirected by the second prism 104 to light emanating at angles beyond ±60 degrees. Therefore, when the included angle x is set between 120 and 130 degrees, light near ±20 degrees can be effectively suppressed. Specifically, in Embodiment 4, an included angle x of 120 degrees suppresses light approximately ±25 degrees, while in Embodiment 3, an included angle x of 130 degrees suppresses light approximately ±15 degrees. The suppressed light is actually redirected and diverged to a larger angle, such as approximately ±60 degrees or even beyond ±80 degrees. In this way, Embodiments 3 and 4, compared to the comparative example, can highlight the local brightness near 0 degrees and enhance the luminance and contrast near the viewing angle.

[0043] For gaming monitors, slight light leakage may occur in the LCD panel at wider viewing angles, resulting in insufficient black levels. To improve this issue, this embodiment reduces or suppresses the light energy around a viewing angle of approximately 20 degrees. The chance of viewing the display device from angles beyond ±60 degrees is very low. Even if the light is redirected to angles beyond ±60 degrees, viewers of gaming monitors typically do not view the screen from such large angles (e.g., 60 or 80 degrees), so it is unlikely to significantly affect the actual viewing experience or display quality.

[0044] In other words, the arrangement density y of the second prism 104 of the optical film structure 100 and the included angle x satisfy the design of the first density mathematical formula, which can improve the contrast of the display device in the normal viewing angle range.

[0045] Please see Figure 6 The arrangement density y of the second prism 104 and the included angle x can further satisfy the second density mathematical expression and the third density mathematical expression, where the second density mathematical expression is 0 < y ≤ 0.0002x. 2 -0.0318x+1.4829, while the mathematical expression for the third density is 0<y≤0.00000277x. 3 -0.000654x 2 +0.05165x-1.21674. (For example...) Figure 6 As shown, as the first density formula, the second density formula, and the third density formula are satisfied, the value of the arrangement density y decreases. That is to say, when the highest arrangement density setting is required, the first density formula will be used, which has better spectral uniformity. Conversely, when the lowest arrangement density setting is required, the third density formula will be used. Although the spectral uniformity is reduced, higher luminance can be obtained. When both spectral uniformity and luminance need to fall within the equilibrium range, the second density formula will be used.

[0046] For example, when the included angle x is 60 degrees, the permutation density y that satisfies the first density mathematical formula is approximately no greater than 64%, the permutation density y that satisfies the second density mathematical formula is approximately no greater than 29%, and the permutation density y that satisfies the third density mathematical formula is approximately no greater than 13%.

[0047] Please see Figure 7 and Figures 8A to 8C , Figure 7 Examples 5 to 8 are optical film structures with an included angle x of 60 degrees and arrangement densities y of 50%, 40%, 30%, and 20%, respectively. The comparative example is an optical film that only has a prism that concentrates light outwards at a positive angle but does not have the aforementioned second prism 104. The relative brightness is the result of normalizing the 0-degree light output brightness of the comparative example and examples 5 to 8. Figures 8A to 8C These are schematic diagrams showing the emitted light brightness of Examples 5 to 7, respectively. Figure 7 and Figures 8A to 8C It can be seen that, compared with Example 7, whose arrangement density y is close to the curve of the second density mathematical formula and Example 8, whose arrangement density y is between the curve of the second density mathematical formula and Example 8, Example 5 and Example 6 have better brightness uniformity within ±40 degrees, while Example 7 and Example 8 have higher luminance at the positive viewing angle (i.e., 0 degrees).

[0048] In detail, such as Figure 7 As shown, the relative brightness decrease in Examples 5 and 6 between 0 degrees and ±40 degrees is milder than that in Examples 7 and 8, but the luminance of Examples 7 and 8 at 0 degrees is higher than that of Examples 5 and 6 at 0 degrees. Regarding Example 5... Figure 8A and Example 6 Figure 8B The darkest region with the highest luminance in the center of the light output brightness diagram is distributed between 0 degrees and ±30 degrees, and the second darkest region with the second highest luminance is distributed between ±30 degrees and ±40 degrees. In Example 7... Figure 8C The darkest region with the highest luminance in the center of the light output brightness diagram is distributed between 0 degrees and ±20 degrees, while the second darkest region with the second highest luminance is distributed between ±20 degrees and ±30 degrees.

[0049] Therefore, when the display device requires brightness uniformity, the second prism 104 of the optical film structure 100 can be designed with an arrangement density y that is closer to the curve of the first density mathematical formula. When the display device requires positive viewing angle luminance, the second prism 104 of the optical film structure 100 can be designed with an arrangement density y that is closer to the curve of the third density mathematical formula. When the display device needs to have both brightness uniformity and positive viewing angle luminance, the second prism 104 of the optical film structure 100 can be designed with an arrangement density y that is closer to the curve of the second density mathematical formula.

[0050] In addition, such as Figure 1 , Figure 9A and Figure 9B As shown, an observation position O is defined at a certain distance in front of the display device 1, and the display device 1 is tilted to form a first side and a second side, with the first side being closer to the observation position O than the second side. In actual implementation, as... Figure 9A As shown, the first side refers to one of the left PL and right PR of the display device 1, and the second side refers to the other of the left PL and right PR of the display device 1, as shown. Figure 9B As shown, the first side refers to one of the upper side PT and the lower side PB of the display device 1, and the second side refers to the other of the upper side PT and the lower side PB of the display device 1. The left side PL, the right side PR, the upper side PT and the lower side PB are located at one-tenth of the side length from the edge. The first side and the second side respectively form the first side visible brightness and the second side visible brightness.

[0051] Specifically, when light enters the optical film structure 100 from either the first surface S1 or the second surface S2, and exits from the other surface S2, the first side and the second side... Figure 9A The middle sections are the right PR and left PL, the first side and the second side are respectively. Figure 9B The lower side PB and the upper side PT are respectively. Therefore, the right side PR and the left side PL of the display device 1 pointed from the observation position O are defined as the first side viewing direction H1 and the second side viewing direction H2, respectively. Alternatively, the lower side PB and the upper side PT of the display device 1 pointed from the observation position O are defined as the first side viewing direction V1 and the second side viewing direction V2, respectively. The center of the display device 1 pointed from the observation position O is defined as the observation frontal viewing direction HN and VN. The observation frontal viewing direction HN and VN are respectively between the first side viewing direction H1 and V1 and the second side viewing direction H2 and V2. The angle between the observation frontal viewing direction HN and VN and the second side viewing direction H2 and V2 is less than the angle between the observation frontal viewing direction HN and VN and the first side viewing direction H1 and V1. The luminance of the second side view is less than the luminance of the first side view and is less than 1.73 times the luminance of the second side view.

[0052] For example, regarding a 27-inch display device, such as Figure 9A As shown, the display device 1 is horizontally deflected by 30 degrees, and the angles between the first side-viewing direction H1 and the second side-viewing direction H2 and the observation front-viewing direction HN are 40 degrees and 17 degrees respectively. Figure 9B As shown, the display device 1 is vertically deflected by 15 degrees, and the angles between the first side-viewing direction V1 and the second side-viewing direction V2 and the observation front-viewing direction VN are 22 degrees and 7 degrees, respectively. When using the optical film structure 100 of this utility model, the arrangement density y of the second prism 104 of the optical film structure 100 and the included angle x satisfy one of the first density mathematical formula, the second density mathematical formula, and the third density mathematical formula. This allows the brightness of the first side-view and the brightness of the second side-view to conform to the above-mentioned magnitude and ratio relationship, that is, the brightness of the second side-view is < the brightness of the first side-view ≦ 1.73 times the brightness of the second side-view. Therefore, it can achieve the 5.10 brightness uniformity-angle dependence in the TCO display 9th generation certification specification.

[0053] Please see Figure 10 , Figure 10 Implementation examples and Figure 1 Most of the components in the embodiments have the same structure and design, so the same technical features will not be described again here. The main difference between the two embodiments is... Figure 10The embodiment employs a double-layer film structure, with the optical film structure 100A including a first film F1 and a second film F2. The first film F1 has a first surface S1 and a bottom surface BS opposite to the first surface S1, and a plurality of first prisms 102 are located on the first surface S1 of the first film F1. The second film F2 has a second surface S2 and a top surface TS opposite to the second surface S2, and a plurality of second prisms 104 are located on the second surface S2 of the second film F2, with the top surface TS located between the second surface S2 and the bottom surface BS. In some embodiments, microstructures can be formed on the bottom surface BS of the first film F1 and / or the top surface TS of the second film F2, which can reduce the moiré pattern of the first prisms 102 and / or the second prisms 104, thereby improving display quality.

[0054] Please see Figure 11 The backlight module 10 includes a light guide plate 200, a light source 300, and an optical film structure 100. The light guide plate 200 has an incident light surface IS and an exit light surface ES. The light source 300 is disposed on the incident light surface IS, and the optical film structure 100 is disposed in front of the exit light surface ES. In other embodiments, the optical film structure included in the backlight module 10 may be... Figure 10 The optical film structure 100A.

[0055] Please see Figure 12 The backlight module 10A includes a light source 300A and an optical film structure 100. The light source 300A includes a substrate 302 and a plurality of light-emitting units 304 arranged on the substrate 302. The optical film structure 100 is disposed in front of the light source 300A. In other embodiments, the optical film structure included in the backlight module 10A may be... Figure 10 The optical film structure 100A.

[0056] The aforementioned optical film structure 100A is mainly located between the diffuser and the reflective polarizing brightening film (Dual Brightness Enhancement Film, DBEF) to replace the ordinary prism sheet. This solves the problem that although the brightness of the ordinary prism sheet can be improved by using a high refractive index material, the viewing angle will be reduced at the same time.

[0057] Please see Figure 13 The display device 1 includes a backlight module 10 and a display panel 20. The display panel 20 is disposed in front of the backlight module 10, and the display panel 20 may be a liquid crystal display panel. In other embodiments, the backlight module included in the display device 1 may be... Figure 12 The 10A backlight module.

[0058] In summary, in the optical film structure, the backlight module including the aforementioned optical film structure, and the display device including the aforementioned backlight module, in at least one embodiment of the present invention, the arrangement density and included angle of the prisms in the optical film structure satisfy the first density mathematical formula 0<y≤-0.00000543x 3 +0.00193x 2 -0.20997x+7.46116 allows for improved brightness uniformity across different viewing angles in display devices. This invention utilizes the design of these second prisms, adjusting their angles and arrangement density to precisely control the light source from another dimension, thereby achieving superior performance in terms of high brightness or high contrast. The horizontal or vertical viewing angle can be freely adjusted according to different application needs, providing a better user experience. Finally, applying the optical film of this invention to backlight modules and display devices not only meets the 5.10 brightness uniformity-angle dependence specification of TCO 9th generation certification but also effectively improves the optical efficiency of the display device, reduces energy consumption, complies with the stringent requirements of international organizations such as the EU for energy conservation and carbon reduction in electronic products, and responds to the urgent need for high-contrast e-sports screen products in recent years. It also offers multiple advantages such as simplified manufacturing processes, reduced costs, and compliance with environmental trends.

[0059] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art should be able to make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection defined by the appended claims.

[0060] [List of Labels in the Attached Image]

[0061] 1: Display device

[0062] 10, 10A: Backlight module

[0063] 20: Display panel

[0064] 100, 100A: Optical film structure

[0065] 102: First Prism

[0066] 104: Second Prism

[0067] 106: Spacing section

[0068] 200: Light guide plate

[0069] 300, 300A: Light source

[0070] 302: Substrate

[0071] 304: Light-emitting unit

[0072] A: Area

[0073] BS: Bottom

[0074] C1: First inclined plane

[0075] C2: Second slope

[0076] D1: First Direction

[0077] D2: Second Direction

[0078] D3: Third direction

[0079] ES: Light-emitting surface

[0080] F1: First diaphragm

[0081] F2: Second diaphragm

[0082] H1, V1: First side view direction

[0083] H2, V2: Second side view direction

[0084] HN, VN: Observe in the direction of direct vision

[0085] IS: Light-receiving surface

[0086] L1, L2: Light rays

[0087] O: Observation position

[0088] P: Spacing

[0089] PB: Lower side

[0090] PL: Left side

[0091] PR: Right side

[0092] PT: Upper side

[0093] S1: First surface

[0094] S2: Second surface

[0095] TS: Top surface

[0096] W: Width

[0097] x: included angle

[0098] θ: Angle.

Claims

1. An optical film structure, characterized by, It has opposing first and second surfaces, and includes: A plurality of first prisms are located on the first surface, wherein each of the first prisms extends along a first direction; and A plurality of second prisms are located on the second surface, each second prism extending along a second direction different from the first direction. The plurality of second prisms have an arrangement density y, and each second prism has a first inclined plane and a second inclined plane connected to each other, with an angle x between the first inclined plane and the second inclined plane. The arrangement density y and the angle x satisfy a first density mathematical expression, which is 0 < y ≤ -0.00000543x. 3 +0.00193x 2 -0.20997x+7.46116.

2. The optical film structure of claim 1, wherein, Each of the second prisms has a width W, and the arrangement density y is calculated via a function, wherein the function is wherein P is the pitch of any two adjacent second prisms, and W is the width of each of the spacing portions.

3. The optical film structure of claim 1, wherein, Each of the second prisms is a strip-shaped groove or a strip-shaped rib.

4. The optical film structure of claim 1, wherein, The first direction is perpendicular to the second direction.

5. The optical film structure of claim 1, wherein, The arrangement density y and the included angle x further satisfy a second density mathematical formula, the second density mathematical formula is 0 2 -0.0318x+1.4829.

6. The optical film structure according to claim 1, characterized in that, The arrangement density y and the included angle x further satisfy a third density mathematical formula, the third density mathematical formula is 0 3 -0.000654x 2 +0.05165x-1.21674.

7. The optical film structure of claim 1, wherein, include: A first diaphragm having a first surface and a bottom surface opposite to the first surface, wherein the plurality of first prisms are located on the first surface of the first diaphragm; as well as A second diaphragm has a second surface and a top surface opposite to the second surface, wherein a plurality of second prisms are located on the second surface of the second diaphragm, and the top surface is located between the second surface and the bottom surface.

8. A backlight module, characterized in that, include: A light guide plate, which has a light-incident surface and a light-outcrying surface; A light source, which is disposed on the light-incident surface; as well as The optical film structure according to any one of claims 1 to 7 is disposed in front of the light-emitting face.

9. A backlight module, characterized in that, include: A light source, comprising a substrate and a plurality of light-emitting units arranged on the substrate; as well as The optical film structure according to any one of claims 1 to 7 is disposed in front of the light source.

10. A display device, characterized by comprising: include: The backlight module according to claim 8 or 9; as well as The display panel is located in front of the backlight module.

11. The display device according to claim 10, wherein A viewing position is defined at a certain distance in front of the display device. The display device is tilted to form a first side and a second side. The first side is closer to the viewing position than the second side. The first side and the second side respectively form a first side-viewing luminance and a second side-viewing luminance. The direction from the viewing position to the first side and the second side is defined as the first side-viewing direction and the second side-viewing direction, respectively. The direction from the viewing position to the center of the display device is defined as the front-viewing direction. The front-viewing direction is between the first side-viewing direction and the second side-viewing direction. The angle between the front-viewing direction and the second side-viewing direction is less than the angle between the front-viewing direction and the first side-viewing direction. The second side-viewing luminance is less than the first side-viewing luminance and ≤ 1.73 times the second side-viewing luminance.

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