Backlight module and display device with multiple cone structures designed in optical film

Abstract

A backlight module and a display device are provided in which a plurality of cone structures are designed in an optical film, the backlight module including a light guide plate, a light source, and a first optical film. The light guide plate has a light input surface and a light output surface having a normal line. The light source is provided adjacent to the light input surface. The first optical film is provided against the light output surface and includes prisms and a plurality of microstructures arranged in parallel. The extension direction of each prism is perpendicular to the normal line, and each prism faces the light output surface of the light guide plate. Each microstructure is located on a surface of the first optical film facing away from the light guide plate. Each microstructure is a cone structure having a plurality of facets. The plurality of prisms are located between the plurality of microstructures and the light output surface.

Description

[Technical field]

[0001] The present invention relates to a backlight module and a display device in which a plurality of pyramid structures are designed in an optical film, and more particularly to a side-light-incident type backlight module and a display device having the same. [Background technology]

[0002] A conventional backlight module generally has a diffusion sheet to uniformize light. Generally, a conventional diffusion sheet has a plurality of scattering particles, which can scatter light so as to disperse and uniformize the light. However, the diffusion sheet having the scattering particles is generally used as a concealer and has low optical directivity, destroying the high directivity of the light guide plate. To improve the directivity, the haze of the diffusion sheet needs to be reduced, but the concealer is deteriorated. Although the prism sheet is advantageous in improving the luminance, the haze of the upper diffusion sheet and the lower diffusion sheet used in the backlight module affects the luminance and the appearance of the optical sense, making it difficult to further improve the luminance of the conventional backlight module. Therefore, the focus of the design of the backlight module is to maintain the concealer ability while increasing the light collection property of the light output viewing angle and the luminance of the front viewing angle. Summary of the Invention

[0003] One embodiment of the present invention provides a backlight module including an optical film capable of improving the light concentration at a light viewing angle and the brightness at a front viewing angle.

[0004] Another embodiment of the present invention provides a display device including the above backlight module.

[0005] The backlight module according to one embodiment of the present invention includes a light guide plate, a light source, and Optical FilmThe light guide plate has a light input surface and a light output surface, the light output surface having a normal line. The light source is disposed adjacent to the light input surface. Optical Film is disposed on the light output surface and includes a plurality of parallel prisms and a plurality of microstructures, the extension direction of each prism is perpendicular to the normal line, and each prism faces the light output surface of the light guide plate. Each microstructure is: Optical Film The microstructures are located on a surface facing away from the backlight light guide plate, and each microstructure is a multi-faceted pyramidal structure. The prisms are located between the microstructures and the light output surface.

[0006] In one embodiment of the present invention, the backlight module includes a plurality of Prism Sheet These optical films further include Prism Sheet Located between the light output surface Is .

[0007] In one embodiment of the present invention, each prism sheet includes a plurality of juxtaposed prism strips, the extension direction of these prism strips of one prism sheet being perpendicular to the extension direction of these prism strips of the other prism sheet.

[0008] In one embodiment of the present invention, the light exit surface is connected to one side of the light entrance surface, and the light source has a plurality of light emitting diodes arranged along a straight line, with the prism strips of one prism sheet extending parallel to the straight line and the prism strips of the other prism sheet extending perpendicular to the straight line.

[0009] In one embodiment of the present invention, the extension direction of these prisms is perpendicular to the straight line.

[0010] In one embodiment of the present invention, the light exit surface is connected to one side of the light input surface, the light source has a plurality of light emitting diodes arranged in a line, and the extension direction of these prism strips of each prism sheet is neither parallel nor perpendicular to the line.

[0011] In one embodiment of the present invention, the extension direction of these prisms is parallel to the straight line.

[0012] In one embodiment of the present invention, these microstructures are a plurality of adjacent pyramidal cavities.

[0013] In one embodiment of the present invention, these microstructures are a plurality of adjacent pyramidal bumps.

[0014] In one embodiment of the present invention, these microstructures include: Optical Film They are arranged in an array diagonally with respect to one side of the panel.

[0015] In one embodiment of the present invention, the light guide plate has a bottom surface facing the light output surface and a plurality of light guiding structures formed on the bottom surface, each light guiding structure has a light receiving surface and a non-light receiving surface connected to each other. The light receiving surface faces the light traveling direction of the light source, a first included angle is formed between the light receiving surface and the bottom surface, and a second included angle is formed between the non-light receiving surface and the bottom surface. The first included angle and the second included angle are both acute angles, and the first included angle is smaller than the second included angle.

[0016] A display device according to another embodiment of the present invention includes the above backlight module and a display panel provided relative to the backlight module.

[0017] Based on the above, by using these prisms and these micro-structures, the light emitted from the light source is first Optical Film Through these prisms, the effect of improving the directivity occurs, and then the Optical Film The micro-structure of this concealer helps keep the concealer in place. Optical Film The backlight module can maintain the concealing ability and can emit light in a concentrated manner, thereby improving the light concentration at the light emission viewing angle and the brightness at the front viewing angle of the backlight module. [Brief description of the drawings]

[0018] For a more complete understanding of the embodiments and their advantages, reference is made to the following drawings, in which: [Figure 1A] 1 is a schematic plan view of a backlight module according to an embodiment of the present invention; [Figure 1B] FIG. 1B is a schematic cross-sectional view taken along line 1B-1B in FIG. 1A. [Figure 1C] FIG. 2 is a partial schematic plan view of the optical film in FIG. 1B. [Figure 1D] FIG. 4 is a partial schematic plan view of an optical film according to another embodiment of the present invention. [Figure 2A] FIG. 4 is a schematic plan view of a backlight module according to another embodiment of the present invention. [Figure 2B] FIG. 2B is a schematic cross-sectional view taken along the line 2B-2B in FIG. 2A. [Figure 2C] FIG. 2C is a schematic perspective view of the backlight module of FIG. 2B. [Figure 2D] 2C is a schematic plan view of a part of the prism sheet in FIG. 2B. FIG. [Figure 2E] 2C is a schematic plan view of a part of the prism sheet in FIG. 2B. FIG. [Figure 3A] FIG. 11 is a schematic plan view of a plurality of prism sheets in another embodiment of the present invention. [Figure 3B] FIG. 11 is a schematic plan view of a plurality of prism sheets in another embodiment of the present invention. [Figure 4A] FIG. 2 is a spatial luminance distribution diagram of both the comparative backlight module and the backlight module shown in FIG. 1B. [Figure 4B] FIG. 2 is a spatial luminance distribution diagram of both the comparative backlight module and the backlight module shown in FIG. 1B. [Figure 5A] FIG. 11 is a spatial luminance distribution diagram of a backlight module of a comparative example. [Figure 5B] 4A and 4B are spatial luminance distribution diagrams of backlight modules according to several embodiments of the present invention; [Figure 5C] 4A and 4B are spatial luminance distribution diagrams of backlight modules according to several embodiments of the present invention; [Figure 5D] 4A and 4B are spatial luminance distribution diagrams of backlight modules according to several embodiments of the present invention; [Figure 5E] 4A and 4B are spatial luminance distribution diagrams of backlight modules according to several embodiments of the present invention; [Figure 6] FIG. 4 is a schematic cross-sectional view of a backlight module according to another embodiment of the present invention. [Figure 7] 1 is a schematic side view of a display device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In the following description, in order to clarify the technical features of the present application, the dimensions (e.g., length, width, thickness and depth) of elements (e.g., layers, films, substrates and regions, etc.) in the drawings are amplified at different rates and the number of certain elements is reduced. Therefore, the description and interpretation of the following examples are not limited to the number of elements in the drawings and the dimensions and shapes shown by the elements, but should cover the variations in dimensions, shapes and both due to actual recipes and / or tolerances. For example, flat surfaces shown in the drawings may have roughness and / or nonlinear features, and corners shown in the drawings may be rounded. Therefore, the elements shown in the drawings of the present application are mainly schematic and are not intended to accurately depict the actual shapes of the elements, and are not intended to limit the protection scope of the claims of the present application.

[0020] Next, the terms "about", "approximate", "substantially", etc. described in this application not only cover the numerical values ​​and numerical ranges clearly described, but also cover the allowable variation range that can be understood by a person skilled in the art of this application, which is determined by the error occurring during measurement, and this error is due to the limitations of both the measurement system and the recipe conditions, for example. In addition, "about" can represent being within one or more standard variations of the above numerical values, for example, within ±30%, ±20%, ±10%, or ±5%. In this application, the terms "about", "approximate", "substantially", etc. can select an allowable variation range or standard variation depending on the optical properties, etching properties, mechanical properties, or other properties, and do not cover all properties such as the above optical properties, etching properties, mechanical properties, and other properties with a single standard variation.

[0021] FIG 1A is a schematic plan view of a backlight module according to an embodiment of the present invention, and FIG 1B is a schematic cross-sectional view taken along line 1B-1B in FIG 1A. Referring to FIG 1A and FIG 1B, the backlight module 100 includes: Optical Film 110, includes a light guide plate 130 and a light source 190. The light guide plate 130 has a light incident surface 131 and a light exit surface 132, and the light exit surface 132 may have a normal N1 and be connected to one side of the light incident surface 131. The light source 190 is disposed adjacent to the light incident surface 131 and can emit a light beam L1 toward the light incident surface 131. Optical Film 110 is disposed against the light output surface 132 and includes a plurality of juxtaposed prisms 111 and a plurality of microstructures 112 .

[0022] The extension direction E1 of each prism 111 is perpendicular to the normal N1, and each prism 111 faces the light output surface 132 of the light guide plate 130. Each micro-structure 112 has: Optical FilmThe microstructures 112 are located on a surface of the light guide plate 110 facing away from the light guide plate 130, and each microstructure 112 is a pyramidal structure having a plurality of facets 112s, and these prisms 111 are located between these microstructures 112 and the light output surface 132. Also, in FIG. 1A, the microstructures 112 are omitted in order to clarify the orientation of the prisms 111, and in FIG. 1A, the thick lines represent the valleys between two adjacent prisms 111, and the thin lines represent the peaks of each prism 111.

[0023] As shown in FIG. 1B, the light guide plate 130 further has a bottom surface 133, and the light output surface 132 and the bottom surface 133 face each other, and the bottom surface 133 and the light output surface 132 may be both faces of the light guide plate 130. When the light source 190 emits a light ray L1 toward the light input surface 131, the light ray L1 enters the light guide plate 130 from the light input surface 131, and a part of the light ray L1 enters the bottom surface 133 from the light input surface 131. The bottom surface 133 can reflect a part of the light ray L1. For example, the bottom surface 133 can constantly reflect the light ray in the light guide plate 130 by total internal reflection (TIR) ​​to transmit the light ray to the rear of the light guide plate 130. In addition, some of the light rays L1 are deviated from the total reflection by the micro-structures arranged on the bottom surface 133, and the reflection angle is changed. Then, the light rays L1 leave the light guide plate 130 through the light exit surface 132, Optical Film The light beam L1 enters the prism 111 of the prism 110. By deflecting the light in the direction of the normal N1 and reducing the exit angle when passing through these prisms 111, This has the effect of increasing the directivity by concentrating the light.

[0024] Then, the light ray L1 exits the prism 111 Optical Film 110 and through the microstructure 112 Optical Film110. The concealer effect occurs because the micro-structure 112 has multiple facets 112s, which deflect the light beam L1 through the multiple facets 112s and guide it in multiple outgoing directions, thereby avoiding the light beam energy from being too concentrated directly above the micro-structure 112 and maintaining the concealer effect. A typical halftone dot micro-structure or diffusion particle causes the light beam to scatter in an indefinite direction, and the concealer direction cannot be effectively controlled.

[0025] When the light ray L1 passes through the light guide plate 130, Optical Film 110 and then away from the backlight module 100, the prism 111 and the micro-structure 112 can refract the light ray L1, so that the light ray L1 Optical Film The exit angle at 110 is not equal to the exit angle of the light ray L1 at the light guide plate 130, and Optical Film The backlight module 110 can deflect the light ray L1 toward the normal line N1 and emit the deflected light, thereby improving the light concentration of the backlight module at the viewing angle and the brightness at the front viewing angle.

[0026] The backlight module of the prior art, for example, adopts a structure of two diffusion sheets and two prism sheets, and the viewing angle of the light output is skewed by about 60 degrees from the vertical direction of the light output surface 132 of the light guide plate 130, and the directivity is poor, and the total light output energy is not limited to a specific angle, and the anti-peeping effect is low. Optical Film When 110 is used, the directivity can be improved, the total light output energy is relatively concentrated, the light rays are more deflected in the vertical direction of the light output surface 132 of the light guide plate 130, and the light output viewing angle is about 40 to 50 degrees.

[0027] In other words, Optical Film The 110 has the characteristics of high directionality and maintaining concealment, and can further improve the brightness at the front viewing angle, saving energy and increasing range while meeting the future trend of improving brightness.

[0028] Furthermore, the light source 190 also has a plurality of light emitting diodes 191 arranged side by side along a straight line SL1. Specifically, these light emitting diodes 191 may be mounted on a single stripe-shaped circuit board, and these light emitting diodes 191 may be arranged in a single straight line, and may be arranged along the straight line SL1, and these light emitting diodes 191 and the circuit board may be integrated into a single light bar, and the circuit board may be a printed circuit board (PCB) or a flexible printed circuit (FPC). Also, as shown in FIG. 1A, Optical Film The extension direction E1 of these prisms 111 of 110 may be parallel to the straight line SL1.

[0029] FIG. 1C is a cross-sectional view of the Optical Film FIG. 1B is a partial plan view of the Optical Film110 is drawn along the cross section of the cross section line CR1 in FIG. 1C. Referring to FIG. 1B and FIG. 1C, these microstructures 112 may be a plurality of pyramidal recesses adjacent to each other, and the facets 112s may be the side walls of the pyramidal recesses. For example, each microstructure 112 may be a pyramidal recess, so that each microstructure 112 may have four facets 112s (i.e., side walls), and the included angle between the facets 112s on both opposing sides may be about 90 degrees. Therefore, these microstructures 112 may be regular pyramids that are symmetrical with respect to both the X-axis direction and the Y-axis direction, or asymmetrical pyramids that are symmetrical with respect to either one of the X-axis direction and the Y-axis direction and asymmetrical with respect to the other, so that different degrees of light deflection can be generated in different directions to effectively control the concealer effect in different directions. In other embodiments, the microstructures 112 may be a plurality of adjacent pyramidal bumps, the shape of which may be pyramidal, and the facets 112s may be the side surfaces of the pyramidal bumps. Thus, the microstructures 112 may be bumps or pits, and Figures 1B and 1C are merely illustrative and not limiting of the present invention. In Figures 1B and 1C, the microstructures 112 may be: Optical Film 110 are arranged in a matrix along one side of the substrate 110, but in another embodiment shown in FIG. Optical Film These microstructures 112 of 110' Optical Film Alternatively, the electrodes 110 may be arranged in an array diagonally with respect to one side of 110.

[0030] FIG. 2A is a schematic plan view of a backlight module according to another embodiment of the present invention, and FIG. 2B is a schematic cross-sectional view taken along the line 2B-2B in FIG. 2A. Referring to FIG. 2A and FIG. 2B, the backlight module 200 of this embodiment is similar to the backlight module 100 of the previous embodiment. For example, the backlight module 200 also has: Optical Film110, a light guide plate 130, and a light source 190. The following mainly focuses on the differences between the backlight modules 100 and 200. The similarities between the backlight modules 200 and 100 will not be described repeatedly.

[0031] In this embodiment, the light emitting diodes 191 in the light source 190 are also arranged side by side along a straight line SL1. However, unlike the backlight module 200 in the above embodiment, as shown in FIG. Optical Film These prisms 111 of 110 extend along an extension direction E2, which is perpendicular to the straight line SL1. Since the extension direction E1 is parallel to the straight line SL1, the extension direction E1 may be perpendicular to the extension direction E2.

[0032] 2C is a perspective schematic diagram of the backlight module of FIG. 2B. Referring to FIG. 2B and FIG. 2C, the backlight module 200 includes a plurality of Prism Sheet 221 and a diffusion sheet 222, Optical Film 110 is these Prism Sheet 221, the diffusion sheet 222, and the light output surface 132. Prism Sheet 221 may include multiple prism sheets. In the embodiment shown in FIG. Prism Sheet 221 is a prism sheet, and these Prism Sheet 221 is a diffusion sheet 222 Optical Film 110. Also, FIG. 2A shows Prism Sheet 221, the diffusion sheet 222, and the microstructure 112 are omitted. Optical Film The extension direction E2 of these prisms 111 of 110 is clearly shown.

[0033] 2D and 2E show the prism sheets in FIG. 2B (i.e. Prism Sheet 221) is shown in Fig. 2D. Prism Sheet 221 is located at the bottom in FIG. 2B Prism Sheet 221, as shown in FIG. 2E. Prism Sheet 221 is located at the top in FIG. Prism Sheet221. Referring to FIG. 2B to FIG. 2E, each Prism Sheet 221 (i.e., prism sheet) includes a plurality of parallel prism strips 221s. In Figures 2D and 2E, the thick lines represent the valleys between two adjacent prism strips 221s, and the thin lines represent the peaks of each prism strip 221s.

[0034] One of them Prism Sheet The extension direction of these prism strips 221s of 221 is the same as that of the other one. Prism Sheet 221, the direction of extension of these prism strips 221s is perpendicular to the direction of extension of these Prism Sheet 221 can guide most of the light rays L1 to exit along the direction of the parallel normal N1. Prism Sheet The prism strips 221s of 221 extend along an extension direction E2 (as shown in FIG. 2D) and Prism Sheet Since the prism strips 221s of 221 extend along the extension direction E1 (as shown in FIG. 2E), Prism Sheet The extension direction E2 of the prism strip 221s of 221 is Prism Sheet 221 is perpendicular to the extending direction E1 of the prism strips 221s of the light emitting element 221.

[0035] The extension direction E1 is parallel to the straight line SL1, and the extension direction E2 is perpendicular to the straight line SL1. Prism Sheet The extension direction E1 of the prism strip 221s of 221 is parallel to the straight line SL1. Prism Sheet The extension direction E2 of the prism strip 221s of 221 is perpendicular to the straight line SL1. Prism Sheet The extension direction E1 of these prism strips 221s of the other prism sheet (e.g., the upper Prism Sheet The extension direction E2 of these prism strips 221s of 221) is perpendicular to the straight line SL1.

[0036] In particular, in the embodiment shown in FIG. 2D and FIG. 2E, two sheets Prism SheetThe extension directions E1 and E2 of the prism strips 221s of the prism element 221 are parallel and perpendicular to the straight line SL1, respectively. Prism Sheet The extension direction of these prism strips 221s in each of 221 is neither parallel nor perpendicular to the straight line SL1.

[0037] Please refer to Figures 3A and 3B. Prism Sheet 321a and 321b are both Prism Sheet 221, and both include a plurality of parallel prism strips 221s. The differences are: Prism Sheet The extension directions of the prism strips 221s of both 321a and 321b are Prism Sheet This is the only difference from 221.

[0038] Specifically, as shown in FIG. 3A and FIG. 3B Prism Sheet 321a and 321b can be applied to the backlight module 200 in FIG. 2B. For example, Prism Sheet 321a is the upper part in FIG. Prism Sheet 221, as shown in FIG. Prism Sheet 321b is the lower part in FIG. Prism Sheet May be replaced with 221.

[0039] According to the above configuration, Optical Film The effect of high directivity and concealer-maintaining characteristics that occur when using 110 is determined by the arrangement direction of the light-emitting diodes 191 of the light source 190 and Optical Film In accordance with the fact that the extension direction of these prisms 111 in 110 is parallel, the extension direction of these prism strips correspondingly designed for each prism sheet is neither parallel nor perpendicular to the arrangement direction of the light emitting diodes 191 of the light source 190. Prism Sheet The extension directions of these prism strips 221s in each of 221 are neither parallel nor perpendicular to the straight line SL1 (corresponding to the extension direction E1 shown in FIG. 3A and FIG. 3B). Prism Sheet 221 extends along the extension direction E31 and is shown in FIG. Prism Sheet 221 extends along an extension direction E32, neither of which is parallel to nor perpendicular to the extension direction E1, and the extension directions E31 and E32 are perpendicular to each other.

[0040] For example, the included angle A31 between the extension directions E31 and E1 in FIG. 3A may be about 45 degrees, and the included angle A31 between the extension directions E32 and E1 in FIG. 3B may be about 135 degrees. In this way, not only are the extension directions E31 and E32 neither parallel nor perpendicular to the extension direction E1, but the included angle between the extension directions E31 and E32 may be about 90 degrees, that is, both the extension directions E31 and E32 are perpendicular to each other. This can further adjust the direction of the light output viewing angle to the perpendicular direction of the light output surface 132 of the light guide plate 130, so that the light output viewing angle is about 0 degrees, the brightness can be further improved, and the full width at half maximum (FWHM) of the light output energy can be further concentrated, which contributes to improving the anti-peeping effect.

[0041] In addition, these shown in FIG. Prism Sheet The light emitting diode 221 and the diffusion sheet 222 can be applied to the backlight module 100 in the above embodiment. Prism Sheet 221 and a diffusion sheet 222. Optical Film 110 in FIG. Optical Film 110. Therefore, the backlight modules 100 and 200 can be replaced with these Prism Sheet 221 and a diffusion sheet 222.

[0042] 4A and 4B are spatial luminance distribution diagrams of both the comparative example backlight module and the backlight module shown in FIG. 1B, respectively. Note that the spatial luminance distribution diagrams (i.e., FIG. 4A, FIG. 4B, and FIG. 5A to FIG. 5E) are essentially color maps. In the present application, the spatial luminance distribution diagrams are displayed as grayscale images, in which the order of the grayscale degree indicates that the representative luminance changes in the order of decreasing. In other words, in the spatial luminance distribution diagrams of the present application, the lighter the gradation, the higher the representative luminance. Conversely, the darker the gradation, the lower the representative luminance. Also, the spatial luminance distribution diagrams shown in FIG. 4A, FIG. 4B, and FIG. 5A to FIG. 5E are all computer simulation diagrams.

[0043] 4A and 4B, FIG. 4A shows a comparative example of a backlight module, which includes a light source, a light guide plate, and a diffusion sheet containing conventional scattering particles, but does not include any prism sheet. FIG. 4B shows the backlight module 100 shown in FIG. 1B, and the backlight module 100 shown in FIG. 4B is Prism Sheet 221. In addition, the light source and the light guide plate included in the backlight module of the comparative example may be the same as the light source 190 and the light guide plate 130, respectively, as shown in FIG.

[0044] 4A and 4B, which are simulations of observing the luminance distribution from an overhead view of the backlight module of the comparative example and backlight module 100, the vertical and horizontal axes in FIGS. 4A and 4B both represent angles, and the center where the vertical and horizontal axes intersect can represent the central axis of the light output surface of the light guide plate (e.g., light output surface 132 of light guide plate 130).

[0045] 1A, 1B and 4B, taking the backlight module 100 as an example, the center of intersection of the vertical axis and the horizontal axis in FIG. 4B is equal to the central axis OB1 of the light output surface 132 in FIG. 1A. The vertical axis angle in FIG. 4B is equal to the observation angle SA1 shown in FIG. 1B. The observation angle SA1 is the angle between the central axis OB1 and the observation direction OD1, and the absolute value of the observation angle SA1 is between 0 degrees and 90 degrees. When the vertical axis angle in FIG. 4B is zero, it represents that the included angle between the observation direction OD1 and the central axis OB1 is zero, that is, the zero vertical axis angle represents that the brightness of the backlight module 100 is observed from the central axis OB1.

[0046] When the angle of the vertical axis in FIG. 4B is a negative value, the observation direction OD1 is biased toward the light input surface 131 of the light guide plate 130, i.e., the vertical axis angle of a negative value means observing the brightness of the backlight module 100 from the side of the light output surface 132 adjacent to the light input surface 131. Conversely, when the angle of the vertical axis in FIG. 4B is a positive value, the observation direction OD1 is deviated from the light input surface 131 of the light guide plate 130, i.e., the vertical axis angle of a positive value means observing the brightness of the backlight module 100 from the side of the light output surface 132 away from the light input surface 131, which represents the observation angle SA1 shown in FIG. 1B. Similarly, the brightness change of the horizontal axis in FIG. 4B represents the brightness distribution between the left and right sides of the backlight module 100 in FIG. 1A.

[0047] The viewing angle of the comparative example backlight module shown in Fig. 4A is about 61 degrees, and the viewing angle of the backlight module 100 shown in Fig. 4B is about 40 degrees, where the viewing angle refers to the peak angle of the light beam. Most of the area in Fig. 4A has a fairly light grayscale, and most of the area in Fig. 4B has a fairly dark grayscale, and only one small block of grayscale has a light grayscale and the color inside it is the darkest grayscale. Thus, Optical Film 110, it can be seen that the light directivity of the backlight module 100 is higher than that of the backlight module of the comparative example.

[0048] In addition, the full width at half maximum (FWHM) of the comparative backlight module in FIG. 4A is about 69 degrees on the vertical axis, and about 40 degrees on the horizontal axis. The backlight module 100 in FIG. 4B has a full width at half maximum (FWHM) of about 40 degrees on the vertical axis, and a full width at half maximum (FWHM) of about 10 degrees on the horizontal axis. Therefore, since the full width at half maximum of the backlight module 100 in FIG. 4B is smaller than that of the comparative backlight module in FIG. 4A, the light directivity of the backlight module 100 in FIG. 4B is higher than that of the comparative backlight module in FIG. 4A, that is, the backlight module 100 shown in FIG. 4B can emit light in a concentrated manner.

[0049] Figure 5A is a spatial brightness distribution diagram of a backlight module of a comparative example, and Figures 5B to 5E are spatial brightness distribution diagrams of backlight modules of several embodiments of the present invention. The definitions of the vertical and horizontal axes in Figures 5A to 5E are all the same as the definitions of the vertical and horizontal axes in Figures 4A and 4B, and the explanation will not be repeated here.

[0050] 5A and 5B, the backlight module of the comparative example shown in FIG. 5A not only includes a light guide plate and a diffusion sheet, but also includes two prism sheets. Optical Film FIG. 5B does not include 110. Optical Film 110 and two prism sheets (i.e. Prism Sheet 2B, 2D and 2E, respectively, that is, the extension direction of the prism strip of one prism sheet is Optical Film The extension direction of the prism strips of the other prism sheet is perpendicular to the extension direction of the prisms 111 (extension directions E1 and E2, respectively).

[0051] These prism sheets (e.g. Prism Sheet221) can guide the light rays so that most of the light rays of the backlight module are emitted along the normal (e.g., normal N1 in FIG. 1B). Therefore, the viewing angles of the backlight modules in both FIG. 5A and FIG. 5B are about 0 degrees. Next, the brightness half-width on the vertical axis of the comparative backlight module in FIG. 5A is about 45 degrees with the brightness half-width on the horizontal axis. The brightness half-width on the vertical axis of the backlight module in FIG. 5B is about 38 degrees, and the brightness half-width on the horizontal axis is about 31 degrees. Thus, the backlight module in FIG. 5B can emit light rays in a concentrated manner, have higher light directivity than the comparative backlight module in FIG. 5A, and improve the brightness by about 15%. In this architecture, the microstructure 112 shown in FIG. 1D is used. Optical Film 2A. Optical Film 1A. These prisms 111 of 110 extend along the extension direction E2. Optical Film 110, the energy of the FWHM can be more concentrated than in the embodiment in which these prisms 111 extend along the extension direction E1, resulting in an even greater increase in brightness.

[0052] FIG. 5C is a spatial luminance distribution diagram of the backlight module of another embodiment shown in FIG. 3A and FIG. 3B of the present invention. Referring to FIG. 5C, FIG. Optical Film 110, two prism sheets (i.e. Prism Sheet 5C shows the backlight module 100 after mounting the prism sheet 221 and the diffusion sheet 222. However, unlike FIG. 5B, in the backlight module shown in FIG. 5C, the installation of these two prism sheets is as shown in FIG. 3A and FIG. 3B respectively, that is, the extending directions of the prism strips of these two prism sheets are both Optical Film The prism strips of one prism sheet are oriented at 45 degrees, and the prism strips of the other prism sheet are oriented at 135 degrees, as shown in FIGS. 3A and 3B.

[0053] In the embodiment shown in FIG. 5C, these prism sheets (e.g. Prism Sheet 221) can guide the light rays to exit along the normal (for example, normal N1 in FIG. 1B), so that the viewing angle of the backlight module in FIG. 5C is about 0 degrees. Next, the brightness half-width on the vertical axis of the backlight module in FIG. 5C is about 34 degrees, and the brightness half-width on the horizontal axis is about 30 degrees. Therefore, compared with the comparative example backlight module in FIG. 5A, the backlight module in FIG. 5C can emit light rays in a concentrated manner, have good light directivity, and improve the brightness by about 20%.

[0054] 5D and 5E are spatial luminance distribution diagrams of a backlight module according to another embodiment of the present invention. FIG. 5D and FIG. 5E are both diagrams of the backlight module 200 shown in FIG. 2A and FIG. 2B, i.e., Optical Film 5D shows that these prisms 111 of 110 extend along an extension direction E2. However, the backlight module 200 shown in FIG. Optical Film Add 110, but Prism Sheet 5D. FIG. 5E shows a complete backlight module 200, in which the orientation of the prism strips of one prism sheet is 0 degrees and the orientation of the prism strips of the other prism sheet is 90 degrees, as shown in FIG. 2A. The viewing angle of the backlight module 200 in FIG. 5D is about 52 degrees, the brightness half width on the vertical axis is about 24 degrees, and the brightness half width on the horizontal axis is about 20 degrees. Thus, compared with the comparative example backlight module in FIG. 4A, the viewing angle of the backlight module 200 in FIG. 5D is about 52 degrees, the brightness half width on the horizontal axis is about 24 degrees, and the brightness half width on the vertical axis is about 20 degrees. Therefore, compared with the comparative example backlight module in FIG. 4A, the viewing angle of the backlight module 200 in FIG. 5D is about 52 degrees, the brightness half width on the vertical axis is about 24 degrees, and the brightness half width on the horizontal axis is about 20 degrees. Prism Sheet In the absence of the light emitting diode 221 and the diffusion sheet 222, the backlight module 200 shown in FIG. 5D has excellent light directivity and can generate a spectral effect, and can provide sufficient brightness to the viewing angles on both the left and right sides (the light areas on both sides and the dark and white areas in the light areas).

[0055] In FIG. 5E, these Prism Sheet 221 (i.e., prism sheet) guides the light beam to the backlight module 200 ( Prism Sheet The viewing angle of the backlight module 200 (including the light emitting diode 221 and the diffusion sheet 222) is about 0 degrees. Next, the brightness half width on the vertical axis of the backlight module 200 shown in Fig. 5E is about 34 degrees, and the brightness half width on the horizontal axis is about 27 degrees. Compared with the comparative example in Fig. 5A, the backlight module 200 in Fig. 5E has good light directivity, and can essentially concentrate the spectral effect in Fig. 5D at the front viewing angle (the central light color area and the dark and white areas in the light color area), and can improve the brightness by about 20%.

[0056] 6 is a schematic cross-sectional view of a backlight module according to another embodiment of the present invention. Referring to FIG. 6, a backlight module 600 of this embodiment is similar to the backlight module 100 of the previous embodiment, and the difference between the backlight modules 600 and 100 is that a light guide plate 630 included in the backlight module 600 is different from the light guide plate 130 in the previous embodiment. The following mainly describes the difference between the backlight modules 600 and 100, and the same features of the two will not be basically repeated.

[0057] Specifically, the light guide plate 630 has a bottom surface 633 and a plurality of light guiding structures 639 formed on the bottom surface 633, where each light guiding structure 639 has a light receiving surface 639a and a non-light receiving surface 639b connected to each other, and the light receiving surface 639a faces the traveling direction of the light ray L1 from the light source 190. As shown in Fig. 6, a first included angle A61 is formed between the light receiving surface 639a and the bottom surface 633, and a second included angle A62 is formed between the non-light receiving surface 639b and the bottom surface 633, where the first included angle A61 and the second included angle A62 are both acute angles, and the first included angle A61 is smaller than the second included angle A62.

[0058] When the light source 190 emits a light ray L1 toward the light-entering surface 631 of the light guide plate 630, the light ray L1 enters the light guide plate 630 from the light-entering surface 631, and some of the light ray L1 enters the light-guiding structure 639, for example, the light-receiving surface 639a. The light ray L1 is reflected by the light-guiding structure 639 (for example, the light-receiving surface 639a), and the light ray L1 exits from the light-exiting surface 632 of the light guide plate 630. With this design, the area of ​​the light-receiving surface 639a can be enlarged and the area of ​​the non-light-receiving surface 639b can be reduced, so that the light-receiving surface 639a has a higher probability of reflecting the light ray to cause the light ray to exit from the light-exiting surface 632 of the light guide plate 630, thereby Optical Film It is used in 110 and contributes to improving the directivity.

[0059] The backlight module 600 further includes a light-reflecting sheet 680, which is located below the light guide plate 630 and faces a bottom surface 633. The light guide plate 630 is in contact with the light-reflecting sheet 680. Optical Film 110. When the light ray L1 enters the light guiding structure 639, the light guiding structure 639 can not only reflect the light ray L1, but also refract the light ray L1, as shown in FIG. 6. When the light guiding structure 639 refracts the light ray L1, the light ray L1 enters the light reflecting sheet 680. The light reflecting sheet 680 can reflect the light ray L1 to make the light ray L1 enter the light guide plate 630 again, so that more light ray L1 can be emitted from the light output surface 632. In this way, the brightness of the backlight module 600 is improved.

[0060] The backlight module 600 in FIG. Prism Sheet 221 and a diffusion sheet 222 (shown in FIG. 2B), or a plurality of Prism Sheet 3A and 3B. That is, in the backlight module 200 shown in FIG. 2B, the light guide plate 130 may be replaced with the light guide plate 630 shown in FIG. 6. Optical Film 110 in FIG. Optical Film 110. That is, in FIG. Optical FilmThese prisms 111 of 110 may extend along an extension direction E1 or E2.

[0061] 7 is a schematic side view of a display device according to an embodiment of the present invention. Referring to FIG. 7, the display device 700 includes a backlight module 710 and a display panel 720, where the display panel 720 is disposed relative to the backlight module 710 and positioned above the light-emitting surface of the backlight module 710 so that the backlight module 710 can emit light toward the display panel 720.

[0062] The backlight module 710 may be the backlight module 100, 200 or 600 in the above embodiment, or any combination of the backlight modules 100, 200 and 600, for example, a plurality of Prism Sheet 221 and the diffusion sheet 222. Thus, the backlight module 710 may be Optical Film 110. The display panel 720 may be, for example, a transmissive display panel such as a liquid crystal display panel. Optical Film 110 maintains the concealer ability and can improve the light directivity of the backlight module 710 by concentrating the emission of light L1, so that the backlight module 710 can emit high-brightness light uniformly, improve the concentration of the emission viewing angle and the brightness at the front viewing angle, and at the same time have a concealer effect, thereby improving the brightness and uniformity of the display panel 720.

[0063] Although the embodiments of the present invention have been disclosed as above, they are not intended to limit the present invention, and a person skilled in the art to which the present invention pertains may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is based on the scope of protection defined by the appended claims. [Explanation of symbols]

[0064] 100, 200, 600, 710 Backlight Module 110, 110' Optical Film 111 Prism 112 Microstructure 112s Facet 130, 630 light guide plate 131, 631 Light entrance surface 132, 632 light emission surface 133, 633 Bottom 190 Light source 191 Light Emitting Diode 221, 321a, 321b Prism Sheet 221s Prism Strip 222 Diffusion Sheet 639 Light guide structure 639a Photosensitive surface 639b Non-light receiving surface 680 Light Reflective Sheet 700 Display device 720 Display Panel A31 Enclosing angle A61 First angle A62 Second angle CR1 cross section line E1, E2, E31, E32 Extending direction L1 ray N1 Normal OB1 center axis OD1 Observation direction SA1 Observation angle SL1 Straight Line

Claims

1. A backlight module in which a plurality of cone structures are designed on an optical film, a light guide plate having a light input surface and a light output surface having a normal line; a light source disposed adjacent to the light entrance surface; an optical film provided on the light output surface, the optical film includes a plurality of juxtaposed prisms and a plurality of microstructures; The extension direction of each of the prisms is perpendicular to the normal line, and each of the prisms faces the light output surface of the light guide plate, Each of the microstructures is located on a surface of the optical film facing away from the light guide plate, and each of the microstructures is a pyramidal structure having a plurality of facets, and a plurality of the prisms are located between the plurality of the microstructures and the light output surface; The light exit surface is connected to one side of the light entrance surface, and the light source has a plurality of light emitting diodes arranged along an arrangement direction. A backlight module with multiple cone structures designed into the optical film.

2. The optical film may further include a plurality of prism sheets, each of which includes a plurality of prism strips arranged in parallel, and the optical film may be located between the plurality of prism sheets and the light output surface. A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 1.

3. The extension direction of the plurality of prism strips of the prism sheet is perpendicular to the extension direction of the plurality of prism strips of the other prism sheet. A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 2.

4. The extension direction of the prisms of the optical film is perpendicular to the arrangement direction of the plurality of light-emitting diodes and is aligned with the extension direction of the plurality of prism strips of the prism sheet. A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 2.

5. The extension direction of the plurality of prism strips of the prism sheet is parallel to the arrangement direction, and the extension direction of the plurality of prism strips of the other prism sheet is perpendicular to the arrangement direction. A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 4.

6. The extension direction of the plurality of prism strips of each of the prism sheets is neither parallel nor perpendicular to the arrangement direction, A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 2.

7. The extension direction of the prism is aligned with the arrangement direction of the plurality of light emitting diodes. A backlight module, in which a plurality of cone structures are designed on the optical film according to claim 6.

8. The plurality of microstructures are arranged in an array obliquely with respect to one side of the optical film. A backlight module, comprising the optical film according to claim 1 , and a plurality of cone structures designed thereon.

9. The light guide plate has a bottom surface facing the light output surface and a plurality of light guide structures formed on the bottom surface, each of the light guide structures has a light receiving surface and a non-light receiving surface connected to each other, the light receiving surface faces the light traveling direction of the light source, the light receiving surface forms a first included angle with the bottom surface, and the non-light receiving surface forms a second included angle with the bottom surface, the first included angle and the second included angle are both acute angles, and the first included angle is smaller than the second included angle. A backlight module, comprising the optical film according to claim 1 , and a plurality of cone structures designed thereon.

10. A display device, comprising: A backlight module in which a plurality of cone structures are designed on the optical film according to any one of claims 1 to 7; a display panel disposed relative to the backlight module; Display device.

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