Optical film structure, backlight module and display device
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- RADIANT OPTO ELECTRONICS CORP
- Filing Date
- 2025-07-25
- Publication Date
- 2026-07-14
Smart Images
Figure CN224501100U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an optical film structure, and also to a backlight module and display device including the above-described optical film structure. Background Technology
[0002] As competition in the automotive market intensifies and the use of smart cockpits becomes increasingly widespread, in-vehicle displays typically offer wide viewing angles to accommodate multiple users simultaneously. However, in certain situations or contexts, it's necessary to restrict and reduce the viewing direction and range, leading to the development of privacy technologies for in-vehicle displays. Current privacy technologies on the market achieve this by incorporating louvered films within the backlight module. However, the louvered films offer limited control over the light-emitting angle and are difficult to fine-tune for specific areas within the visible range, especially in high-brightness environments where their privacy protection is insufficient. Furthermore, existing privacy films may suffer from high costs and low efficiency during manufacturing. Utility Model Content
[0003] One embodiment of this utility model provides an optical film structure that can adjust the direction of light travel to reduce the light emission level in a specific area, thereby helping to improve the privacy protection effect in that specific area.
[0004] One embodiment of this utility model provides a backlight module, including the aforementioned optical film structure and a light source. The light source is located on one side of the optical film structure and is used to emit light toward the optical film structure.
[0005] One embodiment of this utility model provides a display device, including a backlight module and a display panel as described above. The display panel is located on one side of the backlight module, and the optical film structure of the backlight module is located between the light source and the display panel.
[0006] Based on the above, at least one embodiment of this utility model achieves a privacy protection effect by setting a grid layer or grid sheet in the optical film structure. Furthermore, a prism array layer or prism array sheet is set on the grid layer (or grid sheet) to change the direction of light passing through the prism array layer (or prism array sheet). The refractive properties of the prism are used to further control the direction of light propagation, creating a displacement light field effect, thereby improving privacy. In this way, the light emission range can be fine-tuned to enhance the privacy protection effect in a designated area. Attached Figure Description
[0007] The features of this utility model can be understood from the following detailed description and accompanying drawings. It should be noted that many features are not drawn to industrial standard scale. In fact, for clarity of discussion, the dimensions of various features may be arbitrarily increased or decreased.
[0008] Figure 1 A cross-sectional schematic diagram of an optical film structure according to an embodiment of the present invention is shown.
[0009] Figure 2A A top view showing the light field distribution as light passes through a conventional optical film.
[0010] Figure 2B A top view illustrating the light field distribution of light passing through an optical film structure according to an embodiment of the present invention.
[0011] Figure 2C Draw a diagram showing the refraction of light rays after refraction through the first plane of the light-transmitting prism.
[0012] Figure 2D A cross-sectional view of a transparent prism according to an embodiment of the present invention is shown.
[0013] Figure 2E Plot the relationship between θ1 and the offset angle α.
[0014] Figure 2F Draw a diagram showing the refraction of light rays after reflection through the second plane of the light-transmitting prism.
[0015] Figure 3A A top view of a grid layer according to an embodiment of the present invention is shown.
[0016] Figure 3B A top view of a prism array layer according to an embodiment of the present invention is shown.
[0017] Figure 3C Draw Figure 1 A partial three-dimensional schematic diagram of the optical film.
[0018] Figure 4 A cross-sectional schematic diagram of an optical film structure according to an embodiment of the present invention is shown.
[0019] Figure 5 Draw Figure 4 A partial three-dimensional schematic diagram of the optical film structure.
[0020] Figure 6 A top view illustrating the light field distribution of light passing through an optical film structure according to an embodiment of the present invention.
[0021] Figure 7A A partial three-dimensional schematic diagram of the optical film structure according to an embodiment of the present invention is shown.
[0022] Figure 7B A top view of a grid layer according to an embodiment of the present invention is shown.
[0023] Figure 7C A top view of a prism array layer according to an embodiment of the present invention is shown.
[0024] Figure 8 A top view illustrating the light field distribution of light passing through an optical film structure according to an embodiment of the present invention.
[0025] Figure 9A A partial three-dimensional schematic diagram of the optical film structure according to an embodiment of the present invention is shown.
[0026] Figure 9B A top view of a grid layer according to an embodiment of the present invention is shown.
[0027] Figure 9C A top view of a prism array layer according to an embodiment of the present invention is shown.
[0028] Figure 10 A top view illustrating the light field distribution of light passing through an optical film structure according to an embodiment of the present invention.
[0029] Figure 11 A side view of a backlight module according to an embodiment of the present invention is shown.
[0030] Figure 12 A side view schematic diagram of a display device according to an embodiment of the present invention is shown. Detailed Implementation
[0031] In the following text, to clearly present the technical features of this application, the dimensions (e.g., length, width, thickness, and depth) of the elements (e.g., layers, films, substrates, and regions) in the 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 or the size and shape of the elements, but should cover the size, shape, and deviations caused by actual manufacturing processes and / or tolerances. Therefore, the elements presented in the drawings of this application are mainly for illustration and are not intended to accurately depict the actual shape of the elements, nor are they intended to limit the scope of the claims in this application.
[0032] Secondly, the terms "approximately," "approximately," or "substantially" used in this application not only cover explicitly stated numerical values and ranges, but also the permissible deviation range understood by someone skilled in the art to which this utility model pertains. This deviation range can be determined by errors that occur during measurement, such as those arising from limitations of the measurement system or process conditions. Furthermore, "approximately" can indicate a deviation within one or more standard deviations of the aforementioned numerical values, such as ±5%, ±3%, or ±1%. The terms "approximately," "approximately," or "substantially" used in this application can be chosen based on optical properties, etching properties, mechanical properties, or other properties to select an acceptable deviation range or standard deviation, and do not apply a single standard deviation to all optical properties, etching properties, mechanical properties, and other properties.
[0033] Please refer to Figure 1 The optical film structure 100 includes a lattice layer 120 and a prism array layer 140. The lattice layer 120 includes a plurality of light-absorbing lattices 122, which are spaced apart from each other. Each light-absorbing lattice 122 extends along a first major axis direction D1. On the other hand, the prism array layer 140 is disposed on the lattice layer 120. The prism array layer 140 includes a plurality of light-transmitting prisms 142, which are spaced apart from each other, and each light-transmitting prism 142 extends along a strip-shaped direction LD. The first major axis direction D1 is orthogonal to a second major axis direction D2, and the first major axis direction D1 does not intersect with the strip-shaped direction LD.
[0034] In addition, each light-transmitting prism 142 includes a reference plane 142f, a first plane 142a, and a second plane 142b. For example... Figure 1 As shown, a reference surface 142f is disposed on the grid layer 120, a first plane 142a is adjacent to the reference surface 142f, and a second plane 142b is adjacent to both the reference surface 142f and the first plane 142a. A first angle θ1 exists between the reference surface 142f and the first plane 142a, and a second angle θ2 exists between the reference surface 142f and the second plane 142b. It is worth noting that the first angle θ1 and the second angle θ2 are not equal. For example, when... Figure 1 The first included angle θ1 shown can be 30°, and the second included angle θ2 can be 90°.
[0035] Please refer to this as well. Figure 2A as well as Figure 2B ,in Figure 2A The diagram illustrates the light field distribution as light passes through a conventional optical film. Figure 2BThe diagram illustrates the light field distribution of the light field passing through the optical film structure 100 of at least one embodiment of the present invention. Conventional optical films only include a grating layer, where the light-absorbing grating absorbs light rays with large incident angles and restricts the emitted light range to a small angle, thereby achieving a privacy protection effect. However, the optical film structure 100 in the embodiments of the present invention includes a prism array layer 140, and the light-transmitting prisms 142 in the prism array layer 140 can change the direction of light travel. Therefore, when light passes through the grating layer 120 and enters the prism array layer 140, it will be affected by the light-transmitting prisms 142, changing its emitted light direction.
[0036] like Figure 2B As shown, compared to Figure 2A The light emission result, Figure 2B The emitted light field shifts to the right. Specifically, privacy is defined as the ratio of the luminance at a certain position on the emitting surface to the luminance at the center of the emitting surface, and the center of the emitting surface is defined as 0 degrees horizontally and 0 degrees vertically (H0 / V0). Taking the same position P1 in the light field as an example, P1 is at -30 degrees horizontally and +15 degrees vertically (H-30 / V15). With conventional optical films, the privacy visibility at position P1 is 0.62%. On the other hand, with the optical film structure 100 of at least one embodiment of this invention, the privacy visibility at position P1 is 0.45%, a reduction of 27% compared to conventional optical films. In other words, the optical film structure 100 of this embodiment can reduce the privacy visibility in a specific area, thereby improving the privacy effect in that specific area.
[0037] The design utilizes a prism array layer 140 positioned above the light-absorbing grid 122. This structure effectively combines light absorption and refraction, achieving precise light control and enhancing optical performance for improved privacy. The biggest difference between this design and traditional privacy screens is that traditional screens rely solely on the light-absorbing grid's blocking effect to limit light propagation. This invention adds a prism array layer 140 to the light-absorbing grid 122, utilizing the refractive properties of the prisms to further control the light propagation direction, achieving precise light control and creating a shifted light field effect to enhance privacy. This allows for fine-tuning of the light emission range, improving the privacy effect in a specific area.
[0038] For details, please refer to Figure 2C and Figure 2D When ray L1 is incident on the light-transmitting prism 142 from the reference plane 142f, this ray L1 has an exit angle of... It exits from the first plane 142a, and the refractive index of the transparent prism 142 is n, and it satisfies: This provides a theoretical basis for designing and manufacturing high-performance optical film structures. This formula ensures accurate calculation of light refraction, enabling precise control of light.
[0039] Based on the above, the angle of departure... This means that the deflection angle of the light field can be controlled by the first included angle θ1, especially when the first included angle θ1 falls between 0° and 20°. Figure 2E As shown, the two are linearly related. A larger first included angle θ1 will result in a larger exit angle. In other words, the larger the deflection angle of the light field, taking n = 1.53 and θ1 = 10° as an example, the deflection angle is 5.41°, which is slightly larger than half of the first included angle θ1.
[0040] On the other hand, see Figure 2F The second included angle θ2 controls the direction of the reflected light from the second plane 142b. When the second included angle θ2 falls between 60° and 90°, the light L1, after being reflected by the second plane 142b, will exit at a more positive angle, making it less likely to exit from other sides, thus producing a better privacy protection effect.
[0041] Furthermore, since the prism array 240 in the optical film structure 200 is nearly identical (in both material and structure) to the prism array layer 140 in the optical film structure 100, the light-transmitting prism 242 is also nearly identical to the light-transmitting prism 142.
[0042] Furthermore, in this embodiment, the prism array layer 140 is located above the light-absorbing grid 122, allowing the inclined surfaces of the light-transmitting prism 142, namely the first plane 142a and the second plane 142b, to directly contact the air. This increases the degree of light deflection by the inclined surfaces of the light-transmitting prism 142, causing the emitted light to be further away from the normal, thus significantly improving the effect of the shifted light field. Moreover, since the refractive index of the light-transmitting prism 242 falls between 1.46 and 1.62, and this range differs from the refractive index of air (approximately 1), light entering the air from the light-transmitting prism 242 through the first plane 242a or the second plane 242b will be significantly deflected. Furthermore, the direct contact of the inclined surfaces of the light-transmitting prism 142 with the air also avoids light loss and interference introduced by additional media, improving the transmittance and optical performance stability of the optical film structure.
[0043] Compared to the design where the prism array layer 140 is positioned above the light-absorbing grid 122, placing the prism array layer below the light-absorbing grid has some drawbacks. First, placing the prism array layer below the light-absorbing grid increases the film thickness, affecting the overall design and aesthetics of the product. Second, in this design, the prism array layer is not in contact with air. Because the refractive index difference between the prism array layer and the light-absorbing grid is smaller than the refractive index difference between the prism array layer and air, the refracting effect of the inclined plane of the light-transmitting prism is smaller (the emitted light is closer to the normal), resulting in a poorer light field displacement effect and less precise light control compared to the design where the prism array layer is above the light-absorbing grid. Therefore, its privacy protection effect may be inferior to this invention. Furthermore, placing the prism array layer below the light-absorbing grid also increases the manufacturing difficulty and cost of the optical film.
[0044] Please return Figure 1 In some embodiments, the grating layer 120 includes a light-transmitting layer 124. The light-transmitting layer 124 is located between the light-absorbing grating 122 and the prism array layer 140, and a reference surface 142f of each light-transmitting prism 142 is disposed on the light-transmitting layer 124 of the grating layer 120. The light-transmitting layer 124 serves to support the prism array layer 140, and in order to reduce the deflection of light as it passes from the light-transmitting layer 124 through the reference surface 142f of the light-transmitting prism 142 and enters the light-transmitting prism 142, the refractive index of the light-transmitting layer 124 can be similar to the refractive index of the light-transmitting prism 142. For example, when the refractive index of the light-transmitting prism 142 falls within the range of 1.46 to 1.62, the refractive index of the light-transmitting layer 124 also falls within the range of 1.46 to 1.62.
[0045] In addition, in some embodiments, the grating layer 120 also includes a light-transmitting material 126. The light-transmitting material 126 is disposed on the light-absorbing grating 122 and covers the surface 122s of each light-absorbing grating 122. The light-transmitting material 126 is used to protect the surface 122s of the light-absorbing grating 122 to extend its service life, and the overall optical characteristics of the optical film structure 100 can be adjusted according to the characteristics of the light-transmitting material 126. On the other hand, the light-transmitting material 126 forms a flat surface 126s, and then the light-transmitting layer 124 is disposed on this flat surface 126s. In this way, the flatness of the light-transmitting layer 124 can be maintained, and the light-transmitting prisms 142 of the prism array layer 140 are distributed on the flat light-transmitting layer 124.
[0046] It is worth mentioning that, in order to reduce the degree of refraction of light as it passes from the light-transmitting material 126 through the flat surface 126s and enters the light-transmitting layer 124, the refractive index of the light-transmitting material 126 can be similar to that of the light-transmitting layer 124. For example, when the refractive index of the light-transmitting layer 124 falls within the range of 1.46 to 1.62, the refractive index of the light-transmitting material 126 also falls within the range of 1.46 to 1.62.
[0047] Please refer to this as well. Figure 1 , Figure 3A , Figure 3B as well as Figure 3C ,in Figure 3A for Figure 1 Top view of grid layer 120 in the middle. Figure 3B for Figure 1 The top view of the prism array layer 140 in the middle, and Figure 3C Then it is Figure 1 A partial three-dimensional schematic diagram of the optical film structure 100. (See attached diagram.) Figure 3A as well as Figure 3B As shown, the first major axis direction D1 is orthogonal to the second major axis direction D2, and the first major axis direction D1 does not intersect with the strip direction LD. In other words, Figure 1 The light-absorbing grid 122 of the middle grid layer 120 extends in a direction parallel to the light-transmitting prism 142 of the prism array layer 140.
[0048] It is worth mentioning that you should also refer to this. Figure 2B as well as Figure 3C ,because Figure 3C The top view of the optical film structure 100 (i.e., from the perspective of the optical film structure 100) Figure 3C The view from above looking down will produce an optical simulation equivalent to... Figure 2B The top view of the light field distribution. When light ray L1 travels from the lattice layer 120 toward the prism array layer 140 and leaves the prism array layer 140, it will form a light field distribution as shown in the top view. Figure 2B The light field distribution is shown. Because the light ray L1 after leaving the prism array layer 140 points towards... Figure 3C The light shifts to the right, so Figure 2B The light field also shifts to the right. That is, the light ray L1 shifts toward the second plane 142b (i.e., toward the second included angle θ2).
[0049] Please refer to Figure 4 At least one embodiment of this utility model also discloses another optical film structure 200, which is different from... Figure 1 The optical film structure 100, wherein Figure 1 The optical film structure 100 is a single optical film formed by combining a lattice layer 120 and a prism array layer 140. As for... Figure 4 The optical film structure 200 consists of two separate optical films, with the grid layer and prism array layer belonging to different layers. The two embodiments are functionally identical, differing only in structure, and both offer excellent privacy protection. The separate optical films improve manufacturing efficiency and reduce production costs during manufacturing and assembly.
[0050] In this embodiment, Figure 4 The lattice layer of the optical film structure 200 can be referred to as lattice sheet 220, and the prism array layer can be referred to as prism array sheet 240. The lattice sheet 220 includes a plurality of light-absorbing lattices 222, which are spaced apart from each other, and each light-absorbing lattice 222 extends along a first long axis direction D1. The prism array sheet 240 is spaced apart on the lattice sheet 220 and includes a light-transmitting substrate 244 and a plurality of light-transmitting prisms 242. The light-transmitting prisms 242 are spaced apart from each other on the light-transmitting substrate 244, wherein each light-transmitting prism 242 extends along a strip direction LD.
[0051] Furthermore, each light-transmitting prism 242 includes a reference surface 242f, a first plane 242a, and a second plane 242b. The reference surface 242f is disposed above and faces the grid plate 220. The first plane 242a is adjacent to the reference surface 242f, and there is a first included angle θ3 between the reference surface 242f and the first plane 242a. The second plane 242b is adjacent to both the reference surface 242f and the first plane 242a, wherein there is a second included angle θ4 between the reference surface 242f and the second plane 242b, and the first included angle θ3 and the second included angle θ4 are not equal.
[0052] In addition, the grating 220 also includes a light-transmitting material 226. The light-transmitting material 226 is disposed on the light-absorbing grating 222 and covers the surface 222s of each light-absorbing grating 222. The light-transmitting material 226 is similar to the light-transmitting material 126; that is, the light-transmitting material 226 can be used to protect the surface 222s of the light-absorbing grating 222. It is worth mentioning that, in order to reduce the degree of refraction of light as it leaves the light-transmitting material 226 and enters the light-transmitting substrate 244, the refractive index of the light-transmitting material 226 can be similar to the refractive index of the light-transmitting substrate 244. For example, when the refractive index of the light-transmitting substrate 244 falls within the range of 1.46 to 1.62, the refractive index of the light-transmitting material 226 also falls within the range of 1.46 to 1.62.
[0053] Since the lattice layer 220 in the optical film structure 200 of the subsequent embodiment is nearly (in terms of material and structure) the same as the lattice layer 120 in the optical film structure 100, and the prism array layer 240 in the optical film structure 200 is nearly (in terms of material and structure) the same as the prism array layer 140 in the optical film structure 100, the relative positional relationship between the lattice layer 220 and the prism array layer 240 can be referred to Figure 3A and Figure 3B The relative positional relationship between the grid layer 120 and the prism array layer 140.
[0054] Figure 5 for Figure 4 A partial three-dimensional schematic diagram of the optical diaphragm structure 200. Figure 6 This is the light field distribution diagram after the light passes through the optical film structure 200 of the above embodiment. Please refer to it as well. Figure 2A and Figure 6 Compared to Figure 2A The light emission result of (i.e., conventional optical films) Figure 6 The emitted light field shifts to the left. Because... Figure 5 The top view of the optical diaphragm structure 200 (i.e., from the perspective of the optical diaphragm structure 200) Figure 5 The view from above looking down will produce an optical simulation equivalent to... Figure 6 The top view of the light field distribution. When light ray L2 travels from the lattice plate 220 toward the prism array plate 240 and leaves the prism array plate 240, it will form a light field distribution as shown in the top view. Figure 6 The light field distribution is shown. Because the light ray L2 after leaving the prism array plate 240 points towards... Figure 5 The light shifts to the left, so Figure 6 The light field also shifts to the left. That is, the light ray L2 shifts toward the second plane 242b (i.e., toward the second included angle θ4).
[0055] Please refer to this as well. Figure 7A , Figure 7B and Figure 7C Another embodiment illustrated herein has an optical diaphragm structure 300 similar to optical diaphragm structure 100. Specifically, optical diaphragm structure 300 includes a lattice layer 320 and a prism array layer 340, and the lattice layer 320 and prism array layer 340 are substantially equivalent to lattice layer 120 and prism array layer 140, respectively.
[0056] The difference between optical film structure 100 and optical film structure 300 is that the light-absorbing grid 322 in the grid layer 320 extends along the first major axis direction D1, while the plurality of light-transmitting prisms 342 in the prism array layer 340 extend along the strip direction LD. However, the first major axis direction D1 is orthogonal to the second major axis direction D2, and the first major axis direction D1 is also orthogonal to the strip direction LD. In other words, the extension direction of the light-absorbing grid 322 in the grid layer 320 is orthogonal to the extension direction of the light-transmitting prisms 342 in the prism array layer 340. Figure 8 The image shows the light field distribution after light passes through the optical film structure 300 in this embodiment. Please refer to the image below. Figure 2A and Figure 8 Compared to Figure 2A The light emission result, Figure 8 The emitted light field shifts upwards.
[0057] Please refer to this as well. Figure 9A , Figure 9B and Figure 9CIn another embodiment, the optical film structure 400 is similar to the optical film structure 100. Specifically, the optical film structure 400 includes a lattice layer 420 and a prism array layer 440, and the lattice layer 420 and the prism array layer 440 are substantially equivalent to the lattice layer 120 and the prism array layer 140, respectively. Although the first major axis direction D1 and the second major axis direction D2 are orthogonal in this embodiment, the first major axis direction D1 intersects but is not orthogonal to the strip direction LD. Figure 9B As shown, the first major axis direction D1 is between +90° and -90° of the horizontal direction DH, while the second major axis direction D2 is between +90° and -90° of the vertical direction DP.
[0058] In this embodiment, the first included angle θ1 of each light-transmitting prism 442 faces the side adjacent to -90° in the vertical direction DP and the side adjacent to -90° in the horizontal direction DH, and the first included angle θ1 is smaller than the second included angle θ2. In other words, the angle between the normal direction NA of the first plane 442a of the light-transmitting prism 442 and -90° in the vertical direction DP is an acute angle, and the angle between the normal direction NA of the first plane 442a of the light-transmitting prism 442 and -90° in the horizontal direction DH is an acute angle. Figure 10 The image shows the light field distribution after the light passes through the optical film structure 400 in this embodiment. Please refer to the image below. Figure 2A and Figure 10 Compared to Figure 2A The light emission result, Figure 10 The emitted light field is shifted to the lower right. That is, the direction of the shift of the emitted light field is consistent with the normal direction NA of the first plane 442a.
[0059] However, the orientation of the first included angle θ1 in this invention is not limited to the above. In other embodiments (not shown), the first included angle θ1 of each light-transmitting prism 442 can also be the side facing the horizontal direction DH adjacent to +90° and the side facing the vertical direction DP adjacent to +90°, and the first included angle θ1 is smaller than the second included angle θ2. In other words, the angle between the normal direction NA of the first plane 442a of the light-transmitting prism 442 and the horizontal direction DH at +90° is an acute angle, and the angle between it and the vertical direction DP at +90° is also an acute angle. In this way, a relationship with... Figure 10 The opposite result is that the emitted light field shifts to the upper left.
[0060] It is worth mentioning that even when the first major axis direction D1 and the strip direction LD do not intersect, the offset direction of the emitted light field can be changed by adjusting the angle between the normal direction NA of the first plane 142a and the vertical direction DP (or the horizontal direction DH). This is also what causes... Figure 2B as well as Figure 6 The reason for the difference in the light field emitted by the two.
[0061] For example, please return to Figure 3A , Figure 3B as well as Figure 3C Each light-transmitting prism 142 has its first included angle θ1 facing the side adjacent to -90° on the horizontal direction DH. In other words, the first included angle θ1 of the light-transmitting prism 142 faces... Figure 3B To the right of the light-transmitting prism 142, the angle between the normal direction NA of the first plane 142a and the vertical direction DP at +90° is a right angle. The first angle θ1 is smaller than the second angle θ2, and this embodiment can achieve the following... Figure 2B The emitted light field shown is shifted to the right. On the other hand, although not shown in the figure, when the first included angle θ1 of each light-transmitting prism 142 faces the side adjacent to +90° on the horizontal direction DH, and the first included angle θ1 is also smaller than the second included angle θ2, in other words, when the first included angle θ1 of the light-transmitting prism 142 faces... Figure 3B To the left, we can obtain the following: Figure 6 The emitted light field shown is shifted to the left.
[0062] It is worth mentioning that, although not shown in the figures, at least one embodiment of this utility model can be similar to... Figure 4 and Figure 5 The optical film structure 200 in this embodiment differs from the optical film structure 200 in that the first major axis direction D1 is orthogonal to the second major axis direction D2, and the first major axis direction D1 is also orthogonal to the strip direction LD. That is, in this embodiment, the extending direction of the light-absorbing grid 222 of the grid sheet 220 is orthogonal to the extending direction of the light-transmitting prism 242 of the prism array sheet 240. Figure 8 The image shows the light field distribution after light passes through the optical film structure 200 in this embodiment. Please refer to the image below. Figure 2A and Figure 8 Compared to Figure 2A The light emission result, Figure 8 The emitted light field shifts upwards.
[0063] In detail, such as Figure 7A As shown, when the first major axis direction D1 and the strip direction LD are orthogonal, the first included angle θ1 of each light-transmitting prism 142 faces the side adjacent to -90° on the vertical direction DP. In other words, the first included angle θ1 of the light-transmitting prism 142 faces... Figure 7C Above, one can obtain as follows Figure 8 The emitted light field shown is shifted upwards. On the other hand, although not shown in the figure, when the first included angle θ1 of each light-transmitting prism 142 faces the side adjacent to +90° on the vertical direction DP, in other words, when the first included angle θ1 of the light-transmitting prism 142 faces... Figure 7C Below this, the emitted light field will be found to be shifted downwards.
[0064] In addition, although not shown in the figures, another embodiment of this utility model may be similar. Figure 4 and Figure 5 The optical film structure 200 in this embodiment differs from the optical film structure 200 in that the first major axis direction D1 and the second major axis direction D2 are orthogonal, but the first major axis direction D1 intersects the strip direction LD but is not orthogonal. Specifically, the first major axis direction D1 lies between +90° and -90° of the horizontal direction DH, while the second major axis direction D2 lies between +90° and -90° of the vertical direction DP (see reference). Figure 9B and Figure 9C ).
[0065] Please refer to Figure 11 The illustrated backlight module 10 includes the aforementioned optical film structure 100 (or optical film structure 200) and a light source 105. The light source 105 is located on one side of the optical film structure 100 (or optical film structure 200) and is used to emit light L1 toward the optical film structure 100 (or optical film structure 200), wherein the lattice layer 120 (or lattice plate 220) is located between the prism array layer 140 (or prism array plate 240) and the light source 105.
[0066] Please refer to Figure 12 The illustrated display device 1 includes the aforementioned backlight module 10 and display panel 12. The display panel 12 is located on one side of the backlight module 10, wherein the optical film structure 100 (or optical film structure 200) of the backlight module 10 is located between the light source 105 and the display panel 12.
[0067] In summary, privacy protection is achieved by incorporating a grating layer or grating sheet into the optical film structure. Furthermore, a prism array layer or prism array sheet is placed on the grating layer (or grating sheet) to alter the direction of light passing through it, thereby reducing the light emission level in specific areas. This allows for fine-tuning of the light emission range, enhancing the privacy protection effect in designated areas.
[0068] 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 can 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 shall be determined by the claims.
[0069] [Symbol Explanation]
[0070] 1: Display device
[0071] 10: Backlight Module
[0072] 12: Display panel
[0073] 100, 300, 400: Optical film structure
[0074] 105: Light source
[0075] 120, 320, 420: Grid layer
[0076] 122, 222, 322: Light-absorbing grids
[0077] 122s, 126s, 222s: Surface
[0078] 124: Translucent layer
[0079] 126, 226: Translucent materials
[0080] 140, 340, 440: Prism array layers
[0081] 142, 242, 342, 442: Translucent prisms
[0082] 142f, 242f: Reference planes
[0083] 142a, 242a, 442a: First plane
[0084] 142b, 242b: Second plane
[0085] 200: Optical film structure
[0086] 220: Grille plate
[0087] 240: Prism array plate
[0088] 244: Transparent substrate
[0089] D1: First major axis direction
[0090] D2: Second major axis direction
[0091] LD: Strip direction
[0092] DH: Horizontal direction
[0093] DP: Vertical direction
[0094] L1, L2: Light rays
[0095] NA: Normal direction
[0096] P1: Location
[0097] θ1, θ3: First included angle
[0098] θ2, θ4: Second included angle
[0099] Angle of departure.
Claims
1. An optical diaphragm structure, characterized in that, include: The grid layer includes: Multiple light-absorbing grids are arranged at intervals from each other, wherein each of the light-absorbing grids extends along a first major axis; and A prism array layer, disposed on the grid layer, and comprising: Multiple light-transmitting prisms are arranged at intervals from each other, wherein each of the light-transmitting prisms extends along a strip-like direction, and each of the light-transmitting prisms includes: The reference plane is set on this grid layer; A first plane, adjacent to the reference plane, wherein the reference plane and the first plane have a first included angle; and The second plane is adjacent to both the reference plane and the first plane, wherein the reference plane and the second plane have a second included angle, and the first included angle and the second included angle are not equal.
2. The optical film structure as described in claim 1, characterized in that, The grating layer also includes a light-transmitting layer located between the light-absorbing gratings and the prism array layer, with the reference surface of each of the light-transmitting prisms disposed on the light-transmitting layer of the grating layer.
3. The optical film structure as described in claim 1, characterized in that, The grid layer also includes: A light-transmitting material is disposed on the light-absorbing grids and covers the surface of each of the light-absorbing grids.
4. The optical film structure as described in claim 1, characterized in that, The first major axis direction is orthogonal to the second major axis direction, and the first major axis direction intersects the strip direction but is not orthogonal to it.
5. The optical film structure as described in claim 4, characterized in that, The second major axis direction is between +90° and -90° in the horizontal direction, while the first major axis direction is between +90° and -90° in the vertical direction. The first included angle of each of the light-transmitting prisms faces the side adjacent to -90° in the vertical direction and the side adjacent to -90° in the horizontal direction, and the first included angle is smaller than the second included angle.
6. The optical film structure as described in claim 1, characterized in that, The first major axis direction is orthogonal to the second major axis direction, and the first major axis direction is orthogonal to the strip direction.
7. The optical film structure as described in claim 6, characterized in that, The first major axis is between +90° and -90° in the vertical direction, and the first included angle of each of the light-transmitting prisms faces either the side adjacent to +90° in the vertical direction or the side adjacent to -90° in the vertical direction, wherein the first included angle is smaller than the second included angle.
8. The optical film structure as described in claim 1, characterized in that, The first major axis direction is orthogonal to a second major axis direction, and the first major axis direction does not intersect the strip direction.
9. The optical film structure as described in claim 8, characterized in that, The second major axis is between +90° and -90° in the horizontal direction, and the first included angle of each of the light-transmitting prisms faces either the side adjacent to -90° in the horizontal direction or the side adjacent to +90° in the horizontal direction, wherein the first included angle is smaller than the second included angle.
10. The optical film structure as described in claim 1, characterized in that, The first included angle falls between 0° and 20°, and the second included angle falls between 60° and 90°.
11. The optical film structure as described in claim 1, characterized in that, When light rays are incident on the transparent prisms from the reference plane, the light rays exit from the first plane at an exit angle, where the value of the first included angle is θ1 and the value of the exit angle is φ, and the value of the refractive index of the transparent prism is n, which satisfies: n×sinθ1=sin(θ1+φ).
12. The optical film structure as described in claim 1, characterized in that, The first and second planes of each of these translucent prisms are in direct contact with the air.
13. The optical film structure as described in claim 1, characterized in that, The lattice layer and the prism array layer are combined to form a single optical film.
14. The optical film structure as described in claim 1, characterized in that, The lattice layer and the prism array layer are two separate optical films.
15. A backlight module, characterized in that, include: The optical film structure as described in any one of claims 1 to 14; as well as A light source is located on one side of the optical film structure and is used to emit light toward the optical film structure, wherein the lattice layer is located between the prism array layer and the light source.
16. A display device, characterized in that, include: The backlight module as described in claim 15; as well as The display panel is located on one side of the backlight module, wherein the optical film structure of the backlight module is located between the light source and the display panel.