TWI819590B - Backlight module and display device - Google Patents

Abstract

A backlight module including a light source, a light guide element, a first prism sheet, a second prism sheet, and a third prism sheet is provided. The light source is configured to emit an illumination beam. The light guide element is disposed on a transmission path of the illumination beam. The first prism sheet is disposed on the light guide element, and includes a plurality of first prisms. A first top angle of each of the first prisms is towards the light guide element. The second prism sheet is disposed above the first prism sheet, and includes a plurality of second prisms. A second top angle of each of the second prisms is towards the light guide element. The third prism sheet is disposed above the second prism sheet, and includes a plurality of third prisms. A third angle of each of the third prisms is towards a direction away from the light guide element. A display device is also provided.

Description

Backlight modules and display devices

The present invention relates to a light source module and a display device including the same, and in particular, to a backlight module and a display device.

In the field of displays, liquid crystal displays have become one of the common mainstream displays. A liquid crystal display includes a liquid crystal display panel and a backlight module. The main components of the conventional backlight module include a basic light source, a reflective sheet, a light guide plate, a diffusion sheet, and two pixels. The two pixels perpendicular to each other have a function. It limits the viewing angle of the LCD so that most of the light emits within the full viewing angle half-width of 25˚ to -25˚ to achieve the effect of light concentration and brightness.

However, in actual use, for single-person use or displays with high privacy requirements, the backlight module only needs to provide enough forward brightness to meet the user's viewing needs. A larger viewing angle will cause Unnecessary energy consumption. The existing technology can be replaced by a reverse mirror, so that the light emitted in the anti-peep direction is controlled within 20˚ of half-maximum width to meet the demand for collimated light. However, the tilt structure of the reverse mirror needs to be made with two or more slopes to meet the optical requirements. This results in complex structural design and high manufacturing process, making the cost of the reverse mirror much higher than that of general-purpose mirrors. of 稜鏡片. In addition, the retroreflective lens can only have a relatively obvious convergence at the viewing angle perpendicular to the direction of the incident light source (the half-maximum width is, for example, 20°), and the half-maximum width at the parallel viewing angle is still larger (the half-maximum width is, for example, 60°).

The "prior art" paragraph is only used to help understand the content of the present invention. Therefore, the content disclosed in the "prior art" paragraph may contain some conventional technologies that do not constitute common knowledge to those with ordinary knowledge in the technical field. The content disclosed in the "Prior Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by those with ordinary knowledge in the technical field before the application of the present invention.

The present invention provides a backlight module that can converge the emitted light in both horizontal and vertical viewing angle directions, so that the emitted light can be concentrated toward a specific viewing angle to meet the requirement of collimated light emission.

The present invention provides a display device that can converge the emitted light in both horizontal and vertical viewing angle directions, so that the emitted light can be concentrated toward a specific viewing angle, so as to meet the privacy requirements of the display device.

Other objects and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

In order to achieve one, part or all of the above objects or other objects, the present invention provides a backlight module, including a light source, a light guide element, a first lens, a second lens and a third lens. The light source is used to emit an illumination beam, and the light guide element is arranged on the transmission path of the illumination beam. The first lens piece is disposed on the light guide element and includes a plurality of first lenses, wherein the first vertex of each first lens faces the light guide element, and each first lens extends along the first direction. . The second lens is disposed above the first lens and includes a plurality of second lenses, wherein the second vertex of each second lens faces the light guide element, and each second lens extends along the second direction. , and the angle between the second direction and the first direction is greater than 75° and less than 105°. The third lens is disposed above the second lens and includes a plurality of third lenses, wherein the third vertex of each third lens faces a direction away from the light guide element, and each third lens is along the The third direction extends, and the angle between the third direction and the first direction is less than 15°.

In an embodiment of the present invention, the first, second and third stainless steel plates satisfy 160°≦θ1+θ3≦200°, θ2<θ1 and θ2<θ3, and 56°≦θ2≦62° , where θ1 is the angle size of the first vertex angle, θ2 is the angle size of the second vertex angle, and θ3 is the angle size of the third vertex angle.

In one embodiment of the present invention, the light guide element has a light exit surface facing the first lens, a bottom surface facing away from the first lens, and a light incident surface connecting the light output surface and the bottom surface, with the light incident surface facing the light source.

In an embodiment of the present invention, the angle between the first direction and the light incident surface is in the range of 80° to 100°, and the first direction and the second direction are both parallel to the light output surface.

In an embodiment of the present invention, the thickness of the light guide element perpendicular to the light exit surface decreases as it moves away from the light entrance surface.

In an embodiment of the present invention, the first ridges are arranged along the second direction, the second ridges are arranged along the first direction, and the third ridges are arranged along the second direction, and the first direction is perpendicular to in the second direction, and the third direction is parallel to the first direction.

In an embodiment of the present invention, the haze of the second haze sheet is greater than 0% and less than or equal to 50%.

In one embodiment of the present invention, a surface of the second fiber sheet facing the third fiber sheet has an anti-adsorption microstructure.

In an embodiment of the present invention, the backlight module further includes a diffusion sheet or a reflective polarizing brightness enhancement film, which is disposed above the third lens.

In an embodiment of the present invention, the ridge line formed by the first vertex corner of each first ridge, the ridge line formed by the second vertex corner of each second ridge, and the ridge line formed by the second vertex corner of each third ridge. The ridges formed by the third vertex angle are respectively curves or polylines.

In an embodiment of the present invention, the cross section of each first rod perpendicular to the first direction is an isosceles triangle, the cross section of each second rod perpendicular to the second direction is an isosceles triangle, and each The cross section of the third side perpendicular to the third direction is an isosceles triangle.

In order to achieve one, part or all of the above objects or other objects, the present invention provides a display device, including the above-mentioned backlight module and a display panel, wherein the display panel is disposed above the backlight module.

Based on the above, embodiments of the present invention have at least one of the following advantages or effects. In the backlight module and the display device of the embodiment of the present invention, the first and second lens pieces are used with the top angle of the lens facing the light guide element, and the top angle of the lens is directed away from the light guide element. The direction of the third braided piece is greater than 75° and less than 105° between the braided extension direction of the first braided sheet and the braided extension direction of the second braided sheet, and the braided extension direction of the third braided sheet is consistent with that of the first braided sheet. The extension direction of the ridge is less than 15°. Therefore, the backlight module of the embodiment of the present invention can converge the emitted light in both the horizontal and vertical viewing angle directions, so that the emitted light can be concentrated toward a specific viewing angle to meet the requirement of collimated light emission, and the embodiment of the present invention The display device can thus achieve anti-peep effect to meet privacy requirements.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. Directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only for reference to the directions in the attached drawings. Accordingly, the directional terms used are illustrative and not limiting of the invention.

1A is a schematic three-dimensional view of a backlight module according to an embodiment of the present invention. FIG. 1B is a partial cross-sectional schematic view of the backlight module of FIG. 1A cut along the first direction D1. FIG. 2B is a schematic cross-sectional view of the second blade in FIG. 1A cut along the first direction D1, and FIG. 2C is a schematic cross-sectional view of the third blade in FIG. 1A along the second direction D2. Cutaway schematic diagram. Referring to FIGS. 1A to 2C , the backlight module 100 of this embodiment includes at least one light source 110 (in FIG. 1A , multiple light sources 110 are used as an example), a light guide element 120 , a first lens 130 , a second prism The lens 140 and the third lens 150. The light source 110 is used to emit an illumination beam 112 (as shown in FIG. 1B ), the light guide element 120 is disposed on the transmission path of the illumination beam 112 , and the first lens 130 is disposed on the light guide element 120 . In this embodiment, each light source 110 is, for example, a light emitting diode. However, in other embodiments, the light source 110 may also use other light-emitting components. For example, these light-emitting diodes may be replaced by cold cathode fluorescent lamps. The light guide element 120 is, for example, a light guide plate, which has a light exit surface 122 facing the first lens 130, a bottom surface 124 facing away from the first lens 130, and a light incident surface 126 connecting the light exit surface 122 and the bottom surface 124, where the light incident surface 126 toward the light source 110 .

The first lens 130 includes a plurality of first lenses 132, and each first lens 132 has a first vertex 131, wherein these first lenses 132 are disposed on the surface of the first lens 130 facing the light guide element 120. , which means that the first vertex 131 of each first ridge 132 faces the light guide element 120, and each first ridge 130 extends along the first direction D1. It should be noted that the first vertex angle 131 is, for example, the angle at which each first corner 132 is away from the installation surface. The second lens 140 is disposed above the first lens 130 (the first lens 130 is disposed between the second lens 140 and the light guide element 120), and includes a plurality of second lenses 142, wherein each second lens 140 is disposed above the first lens 130. The second vertex 141 of the ridge 142 faces the light guide element 120 . Each second frame 142 extends along the second direction D2, and the angle between the second direction D2 and the first direction D1 is greater than 75° and less than 105°. In this embodiment, the first direction D1 is perpendicular to the second direction D2, for example.

The third casing piece 150 is disposed above the second casing piece 140 (the second casing piece 140 is disposed between the first casing piece 130 and the third casing piece 150), and includes a plurality of third casing pieces 152, each third casing piece 150 is disposed above the second casing piece 140. The ridge 152 has a third vertex 151, wherein these third ridges 150 are disposed on the surface of the third ridge 150 away from the light guide element 120, that is, the third vertex 151 of each third ridge 152 faces away from the light guide element 120. The direction of the optical element 120. Each third side 152 extends along the third direction D3, and the angle between the third direction D3 and the first direction D1 is less than 15°. In this embodiment, the third direction D3 is parallel to the first direction D1. In addition, in this embodiment, the first holes 132 are arranged along the second direction D2, the second holes 142 are arranged along the first direction D1, and the third holes 152 are arranged along the second direction D2. . In addition, in this embodiment, the angle φ1 between the first direction D1 and the light-incident surface 126 falls within the range of 80° to 100°, and the first direction D1 and the second direction D2 are both parallel to the light-emitting surface 122 . In this embodiment, the included angle φ1 is equal to 90°, for example.

In this embodiment, at least one of the light-emitting surface 122 and the bottom surface 124 of the light guide element 120 is provided with an optical microstructure 121 (in FIG. 1B , the optical microstructure 121 is provided on the bottom surface 124 as an example). The optical microstructure 121 may be a protrusion or a depression, such as a protrusion, a depression, a relief, a depression, or a combination thereof. In this embodiment, the optical microstructure 121 is a depression, but the invention is not limited thereto. The illumination beam 112 emitted by the light source 110 enters the light guide element 120 through the light incident surface 126 , and then is continuously and totally reflected by the light exit surface 122 and the bottom surface 124 to be transmitted in the light guide element 120 . On the other hand, after the illumination beam 112 is transmitted to the optical microstructure 121, part of the illumination beam 112 is guided by the optical microstructure 121 toward the light emitting surface 122 and penetrates the light emitting surface 122, and the other part of the illumination beam 112 penetrates the optical microstructure 121. The structure 121 is passed to the reflective sheet 160 disposed under the bottom surface 124 . The reflective sheet 160 reflects the illumination beam 112 so that it penetrates the bottom surface 124 and the light-emitting surface 122 in sequence.

3A is a spot diagram formed when the illuminating beam of FIG. 1B emerges from the light exit surface of the light guide element. FIG. 3B is a spot diagram formed by the illuminating beam of FIG. 1B after passing through the first lens. FIG. 3C is the spot diagram of FIG. 1B . The spot pattern formed by the illumination beam after passing through the second lens, and FIG. 3D is the spot pattern formed by the illumination beam in FIG. 1B after passing through the third lens. In Figures 3A to 3D, the center of the circle refers to the normal direction of the light surface 122, the first circle from the center of the circle refers to the direction 15 degrees from the normal direction, and the second circle from the center of the circle refers to the direction 15 degrees from the normal direction. It refers to the direction that is 30 degrees from the normal direction. For each subsequent circle, the angle with the normal direction increases by 15 degrees, until the outermost circle is the direction that is 90 degrees with the normal direction. , the lower part of the light spot diagram refers to the direction away from the light source 110, and the upper part refers to the direction closer to the light source 110. The whiter color in the light spot diagram refers to the stronger intensity of the illumination beam 112, and the darker color refers to the intensity of the illuminating beam 112. The weaker the intensity.

Please refer to FIGS. 1A, 1B and 3A to 3D. When the illumination beam 112 leaves the light guide element 120 from the light exit surface 122 without entering the first lens 130, the light spot is as shown in FIG. 3A. It is deflected away from the light source 110. one side. When the illumination beam 112 passes through the first lens 130, it is refracted by the first lens 132, and the light energy is evenly divided into two halves in the second direction D2, and the light spot is as shown in FIG. 3B. When the illumination beam 112 passes through the second lens 140, since the extending directions of the second lens 142 and the first lens 132 are perpendicular to each other, the illumination beam 112 is guided by the second lens 142, so that the light spot is in the first direction D1. It converges upward to the central position, as shown in Figure 3C. When the illumination beam 112 passes through the third lens 150, since the extending directions of the third lens 152 and the second lens 142 are perpendicular to each other, and the third vertex 151 of the third lens 152 is far away from the light element 120, the original The light spot divided into two halves in the second direction D2 converges to the center of the viewing angle, as shown in Figure 3D.

In the backlight module 100 of this embodiment, the first and second lens pieces 130 and 140 of the light guide element 120 are oriented with their top angles facing away from the light guide element 120 . The direction of the third braided piece 150 is greater than 75° and less than 105° between the braided extending direction of the first braided sheet 130 and the braided extending direction of the second braided sheet 140, and the braided extending direction of the third braided piece 150 is consistent with The extension direction of the first blade 130 is less than 15°. Therefore, the backlight module 100 of this embodiment can converge the emitted light in both horizontal (for example, the second direction D2 ) and vertical (for example, the first direction D1 ) viewing angles, so that the emitted light can be concentrated toward a specific viewing angle, so as to Meet the requirement of collimated light emission. In addition, while improving the light collimation, the optical utilization rate is also improved, thereby reducing the energy consumption of the backlight module 100 .

In this embodiment, the first lattice piece 130, the second lattice piece 140 and the third lattice piece 150 satisfy 160°≦θ1+θ3≦200°, θ2<θ1 and θ2<θ3, and 56°≦θ2≦62° , where θ1 is the angular size of the first vertex angle 131 , θ2 is the angular size of the second vertex angle 141 , and θ3 is the angular size of the third vertex angle 151 .

In this embodiment, the first micron sheet 130, the second micron sheet 140 and the third micron sheet 150 satisfy 0 micron < P1 ≦ 50 micron, 0 micron < P2 ≦ 50 micron and 0 micron < P3 ≦ 50 micron, where P1 is the pitch of the first ridges 132 , P2 is the pitch of the second ridges 142 , and P3 is the pitch of the third ridges 152 . In this embodiment, the pitch P1 of the first ridges 132 is equidistant, the pitch P2 of the second ridges 142 is equidistant, and the pitch P3 of the third ridges 152 is equidistant. However, in other embodiments, the pitches P1 of the first ridges 132 may be unequal, the pitches P2 of the second ridges 142 may be unequal, and the pitches of the third ridges 152 may be unequal. P3 can be unequal.

In addition, in this embodiment, the cross section of each first ridge 132 perpendicular to the first direction D1 is an isosceles triangle (as shown in FIG. 2A ), and the cross section of each second ridge 142 perpendicular to the second direction D2 The cross section is an isosceles triangle (as shown in FIG. 2B ), and the cross section of each third frame 152 perpendicular to the third direction D3 is an isosceles triangle (as shown in FIG. 2C ). In other words, the first lens 132, the second lens 142 and the third lens 152 can achieve a good light collimation effect without using slopes with more than two different slopes, thus effectively reducing the difficulty of the manufacturing process. , and reduce production costs.

In this embodiment, the surface 143 of the second fiber sheet 140 facing the third fiber sheet 150 has an anti-adsorption microstructure 144 (as shown in detail in FIG. 2B ). The anti-adsorption microstructure 144 can be a concave structure, a convex structure or a combination thereof on the surface 143, or a microstructure (such as diffusion particles) is provided in the area of the second film 140 adjacent to the surface 143 to make the surface 143 have concave or convex structures. The structure can effectively avoid interference phenomena (such as Newton rings) caused by adsorption between the surface 143 and the surface 153 of the third lens piece 150 facing the second lens piece 140, thereby effectively preventing the visual effect from being affected by the adsorption phenomenon. In this embodiment, the haze of the second film 140 is greater than 0% and less than or equal to 50%, where the haze may be contributed by the anti-adsorption microstructure 144. In another embodiment, the anti-adsorption microstructure 144 may not be located on the surface 143, but may be located on the surface 153 of the third film 150.

FIG. 4 is a light intensity distribution diagram of the backlight module in FIG. 1A at viewing angles in the horizontal direction and the vertical direction respectively. Please refer to Figure 1A, Figure 1B and Figure 4. It can be seen from Figure 4 that the light intensity at half maximum (FWHM) of the viewing angle in the horizontal direction (that is, the second direction D2) is 22° (half maximum width range For example, it is 11° to -11°), and the light intensity at the viewing angle in the vertical direction (i.e., the first direction D1) has a half-maximum width of 28° (the half-width range is, for example, 14° to -14°), which greatly reduces the light output. The half-height width of the field. In addition, the light intensity peaks of the horizontal and vertical viewing angles are close to 0° (the light intensity peak of the horizontal viewing angle is, for example, 1°, and the light intensity peak of the vertical viewing angle is, for example, -3°), for example, the light intensity peak The difference between the angle and the front viewing angle is less than 5°, so the backlight module 100 has good light collimation in both the horizontal and vertical directions, which improves the optical utilization rate and thereby reduces the cost of the display device. energy consumption. That is to say, the backlight module 100 of this embodiment can have a smaller half-width of light intensity, and can control the half-width of the outgoing light of the backlight module 100 to be within 30° at the full viewing angle, and can adjust the horizontal and vertical viewing angles. Convergence occurs in both directions, so that the emitted light rays are concentrated toward a specific viewing angle to meet the requirement of collimated light output.

5A is a schematic top view of the relative positional relationship between the first light plate, the light guide element below it and the light source in the backlight module of another embodiment of the present invention. A schematic top view of the second wafer and the light guide element below it. FIG. 5C is a schematic top view of the third wafer and the light guide element below it in the backlight module of FIG. 5A. Please refer to FIGS. 5A to 5C . The backlight module of this embodiment is similar to the backlight module of FIG. 1A , and the differences between the two are as follows. In the backlight module of this embodiment, the angle γ1 between the first direction D1 (ie, the extension direction of the first lens 132) and the light incident surface 126 is greater than 90°, and the second direction D2 (ie, the extension direction of the second lens 142) direction) and the light incident surface 126 is less than 90°, and the angle γ3 between the third direction D3 (ie, the extension direction of the third lens 152) and the light incident surface 126 is greater than 90°. In this embodiment, γ1=γ3, γ1-γ2=90°, and γ3-γ2=90°. By inclining the first direction D1 , the second direction D2 and the third direction D3 relative to the light incident surface 126 , it is possible to effectively prevent the interference structure of the film and the pixels of the display panel (such as a liquid crystal display panel) above the backlight module. Produces moiré. According to the relationship formulas of γ1=γ3, γ1-γ2=90° and γ3-γ2=90°, rotate the first lens 130, the second lens 140 and the third lens 150 at the same time, and compare the results at different placement angles. The difference in brightness ratio of the backlight module is shown in Table 1 below. γ3 90 100 110 120 130 140 150 160 170 180 γ2 0 10 20 30 40 50 60 70 80 90 γ1 90 100 110 120 130 140 150 160 170 180 brightness ratio 1 0.96 0.85 0.73 0.61 0.51 0.42 0.38 0.35 0.33

In Table 1, the unit of the values of γ1, γ2 and γ3 is °. It can be seen from Table 1 that the best brightness value can be obtained when γ2 is 0°. Taking the brightness difference of the backlight module as an acceptable target of ≦5%, the rotation angle can meet the brightness requirements within γ2 ≦10°.

FIG. 6 is a graph showing changes in brightness of the backlight module of FIGS. 1A to 2C under different second vertex angle sizes θ2 of the second lens. Please refer to Figure 2B and Figure 6. It can be seen from Figure 6 that the best brightness value can be obtained when the angle size θ2 of the second vertex angle 141 is 58°, and the brightness reduction of the backlight module is ≦5% as an acceptable target. Below, θ2 falls within the range of 56° to 62° to meet the needs.

FIG. 7 is a schematic three-dimensional view of a backlight module according to another embodiment of the present invention. Referring to FIG. 7 , the backlight module 100a of this embodiment is similar to the backlight module 100 of FIG. 1A , and the differences between the two are as follows. The backlight module 100a of this embodiment further includes an optical film 170, which is disposed above the third film 150. The optical film 170 is, for example, a diffuser or a reflective polarizing brightness enhancement film, and the reflective polarization brightness enhancement film is 3M. DBEF (Dual Brightness Enhancement Film) produced by the company.

When the optical film 170 is a diffuser, the blemish-proofing property of the backlight module 100a can be increased and residual light generated at a large viewing angle can be improved. FIG. 8 is a light intensity distribution diagram of the backlight module in FIG. 7 at viewing angles in the horizontal direction and the vertical direction respectively. Please refer to FIGS. 7 and 8 . It can be seen from FIG. 8 that when the optical film 170 is, for example, a diffuser, the half-width of the light intensity at the viewing angles in the horizontal and vertical directions can be controlled at 32° (the half-width range is, for example, 16°). ° to -16°), and comparing with Figure 4, it can be found that the afterglow at a large viewing angle in the horizontal direction can be further effectively suppressed (for example, the light intensity at a viewing angle greater than 60° is less than 0.2). In addition, when the optical film 170 is a reflective polarizing brightness enhancement film, a similar effect is achieved.

9 is a schematic three-dimensional view of the first, second or third lens of the backlight module according to another embodiment of the present invention. Referring to FIG. 9 , the backlight module of this embodiment is similar to the backlight module of FIG. 1A , and the difference between the two is that in the first 130 a , the second 140 a or the third 150 a , these first The pitches of the ridges 132a may be unequal, the heights of the first ridges 132a may be unequal, the pitches of the second ridges 142a may be unequal, and the heights of the second ridges 142a may be unequal. The heights are unequal, the pitches of the third ridges 152a may be unequal, and the heights of the third ridges 152a may be unequal.

FIGS. 10A and 11A are schematic three-dimensional views of the second lens in the backlight module according to two other embodiments of the present invention. FIG. 10B is a schematic cross-sectional view of the second lens of FIG. 10A , and FIG. 11B is a schematic cross-sectional view of the second lens of FIG. 11A . A schematic cross-sectional view of the blade. Please refer to Figures 10A, 10B, 11A and 11B. The backlight module of this embodiment is similar to the backlight module of Figure 1A, and the difference between the two is that in the backlight module of this embodiment, each The ridge line formed by the first vertex angle of a ridge, the ridge line formed by the second vertex angle of each second ridge, and the ridge line formed by the third vertex angle of each third ridge are curves respectively. , or polyline respectively. For example, the above-mentioned ridge line can fluctuate up and down or swing left and right, and it can be a regular or irregular sinusoidal curve. 10A to 11B take the ridge 145b or 145c of the second vertex 141b or 141c of the second ridge 142b or 142c of the second ridge piece 140b or 140c as an example. Among them, the ridge line 145b is a fold line that undulates up and down, and the ridge line 145c is a curve that swings left and right.

FIG. 12 is a schematic cross-sectional view of a backlight module according to yet another embodiment of the present invention. Referring to FIG. 12 , the backlight module 100d of this embodiment is similar to the backlight module 100 of FIG. 1B , and the differences between the two are as follows. In the backlight module 100d of this embodiment, the thickness T of the light guide element 120d perpendicular to the light exit surface 122 decreases as it moves away from the light entrance surface 126.

In addition, the backlight module 100 of FIG. 1B and the backlight module 100d of FIG. 12 are both side-lit backlight modules. However, in other embodiments, a direct-lit backlight module may also be used, and the light guide plate 120 The bottom surface 124 is located between the light emitting surface 122 and the light source 110 .

FIG. 13 is a schematic diagram of a display device according to an embodiment of the present invention. Referring to FIG. 1B and FIG. 13 , the display device 200 of this embodiment includes a backlight module 210 and a display panel 220 . The backlight module 210 may be any backlight module in the above embodiments, and the backlight module 100 in FIG. 1B is taken as an example below. The display panel 220 is disposed above the backlight module 210 , for example, the light exit surface 122 of the light guide plate 120 faces the display panel 220 . The display panel 220 is, for example, a liquid crystal display panel. However, in other embodiments, the display panel 220 may also be an electrophoretic display panel or other types of display panels. After the illumination beam 112 emerges from the third lens 150, it can enter the display panel 220 to provide a collimated light source for the display panel 220. Therefore, the display device 200 of this embodiment can achieve an anti-peep effect to meet privacy requirements while at the same time It has the advantages of high optical utilization and low energy consumption.

To sum up, embodiments of the present invention have at least one of the following advantages or effects. In the backlight module and the display device of the embodiment of the present invention, the first and second lens pieces are used with the top angle of the lens facing the light guide element, and the top angle of the lens is directed away from the light guide element. The direction of the third braided piece is greater than 75° and less than 105° between the braided extension direction of the first braided sheet and the braided extension direction of the second braided sheet, and the braided extension direction of the third braided sheet is consistent with that of the first braided sheet. The extension direction of the ridge is less than 15°. Therefore, the backlight module of the embodiment of the present invention can converge the emitted light in both the horizontal and vertical viewing angle directions, so that the emitted light can be concentrated toward a specific viewing angle to meet the requirement of collimated light emission, and the embodiment of the present invention The display device can thus achieve anti-peep effect to meet privacy requirements.

However, the above are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. That is, simple equivalent changes and modifications may be made based on the patent scope of the present invention and the description of the invention. All are still within the scope of the patent of this invention. In addition, any embodiment or patentable scope of the present invention does not need to achieve all the purposes, advantages or features disclosed in the present invention. In addition, the abstract section and title are only used to assist in searching patent documents and are not intended to limit the scope of the invention. In addition, terms such as “first” and “second” mentioned in this specification or the scope of the patent application are only used to name elements or to distinguish different embodiments or scopes, and are not used to limit the number of elements. upper or lower limit.

100, 100a, 100d, 210: backlight module

110:Light source

112: Illumination beam

120, 120d: light guide element

121: Optical microstructure

122: Shiny surface

124: Bottom

126: Light incident surface

130, 130a: The first piece of film

131:First corner

132, 132a: The first 稜鏡

140, 140a, 140b, 140c: the second piece

141, 141b, 141c: second vertex

142, 142a, 142b, 142c: The second one

143, 153: Surface

144: Anti-adsorption microstructure

145b, 145c: ridge

150, 150a: The third film

151:Third top corner

152, 152a: The third 稜鏡

160: Reflective sheet

170: Optical film

200:Display device

220:Display panel

D1: first direction

D2: second direction

D3: Third direction

P1, P2, P3: pitch

T:Thickness

θ1: The angle size of the first vertex angle

θ2: The angle size of the second vertex angle

θ3: The angle size of the third vertex angle

γ1, γ2, γ3, φ1: included angle

FIG. 1A is a schematic three-dimensional view of a backlight module according to an embodiment of the present invention. FIG. 1B is a partial cross-sectional view of the backlight module of FIG. 1A cut along the first direction D1. FIG. 2A is a schematic cross-sectional view of the first blade in FIG. 1A cut along the second direction D2. FIG. 2B is a schematic cross-sectional view of the second blade in FIG. 1A cut along the first direction D1. FIG. 2C is a schematic cross-sectional view of the third blade in FIG. 1A cut along the second direction D2. FIG. 3A is a spot diagram formed when the illumination beam of FIG. 1B emerges from the light exit surface of the light guide element. FIG. 3B is a spot diagram formed by the illumination beam of FIG. 1B after passing through the first lens. FIG. 3C is a spot diagram formed by the illumination beam of FIG. 1B after passing through the second lens. FIG. 3D is a spot diagram formed by the illumination beam of FIG. 1B after passing through the third lens. FIG. 4 is a light intensity distribution diagram of the backlight module in FIG. 1A at viewing angles in the horizontal direction and the vertical direction respectively. 5A is a schematic top view of the relative positional relationship between the first light plate, the light guide element below it and the light source in the backlight module according to another embodiment of the present invention. 5B is a schematic top view of the second wafer in the backlight module of FIG. 5A and the light guide element below it. 5C is a schematic top view of the third film in the backlight module of FIG. 5A and the light guide element below it. FIG. 6 is a graph showing changes in brightness of the backlight module of FIGS. 1A to 2C under different vertex angles θ2 of the second lens. FIG. 7 is a schematic three-dimensional view of a backlight module according to another embodiment of the present invention. FIG. 8 is a light intensity distribution diagram of the backlight module in FIG. 7 at viewing angles in the horizontal direction and the vertical direction respectively. 9 is a schematic three-dimensional view of the first, second or third lens of the backlight module according to another embodiment of the present invention. 10A and 11A are schematic three-dimensional views of the second wafer in the backlight module according to two other embodiments of the present invention. FIG. 10B is a schematic cross-sectional view of the second blade of FIG. 10A. FIG. 11B is a schematic cross-sectional view of the second blade of FIG. 11A. FIG. 12 is a schematic cross-sectional view of a backlight module according to yet another embodiment of the present invention. FIG. 13 is a schematic diagram of a display device according to an embodiment of the present invention.

100:Backlight module

110:Light source

120:Light guide element

122: Shiny surface

124: Bottom

126: Light incident surface

130:The first film

131:First corner

132:The first 稜鏡

140: The second film

141:Second vertex

142:The second 稜鏡

143, 153: Surface

144: Anti-adsorption microstructure

150:The third film

151:Third top corner

152:The third 稜鏡

160: Reflective sheet

D1: first direction

D2: second direction

D3: Third direction

φ1: included angle

Claims (11)

A backlight module includes: a light source for emitting an illumination beam; a light guide element disposed on the transmission path of the illumination beam; a first optical film disposed on the light guide element and including a plurality of A first lens, in which a first vertex angle of each of the first lenses faces the light guide element, and each of the first lenses extends along a first direction; a second lens piece, configured It is above the first ridge and includes a plurality of second ridges, wherein a second vertex of each of the second ridges faces the light guide element, and each of the second ridges is along a first Extending in two directions, and the angle between the second direction and the first direction is greater than 75° and less than 105°, wherein the haze of the second haze is greater than 0% and less than or equal to 50%; and a third haze, It is arranged above the second lens and includes a plurality of third lenses, wherein a third vertex angle of each of the third lenses faces a direction away from the light guide element, and each of the third edges The mirror extends along a third direction, and the angle between the third direction and the first direction is less than 15°. The backlight module of claim 1, wherein the light guide element has a light emitting surface facing the first lens, a bottom surface facing away from the first lens, and a light incident connecting the light output surface and the bottom surface. The light incident surface faces the light source. The backlight module of claim 2, wherein the angle between the first direction and the light incident surface is in the range of 80° to 100°, and the first direction and the second direction are both parallel to the light exit surface. . The backlight module according to claim 2, wherein the thickness of the light guide element perpendicular to the light exit surface decreases as it moves away from the light entrance surface. The backlight module of claim 1, wherein the first pixels are arranged along the second direction, the second pixels are arranged along the first direction, and the third pixels are arranged along the first direction. The second direction is arranged, the first direction is perpendicular to the second direction, and the third direction is parallel to the first direction. The backlight module of claim 1, wherein the cross-section perpendicular to the first direction of each of the first pixels is an isosceles triangle, and the cross-section of each of the second pixels perpendicular to the second direction is an isosceles triangle. The cross-section is an isosceles triangle, and the cross-section perpendicular to the third direction of each of the third ribs is an isosceles triangle. A backlight module includes: a light source for emitting an illumination beam; a light guide element disposed on the transmission path of the illumination beam; a first optical film disposed on the light guide element and including a plurality of A first lens, in which a first vertex angle of each of the first lenses faces the light guide element, and each of the first lenses extends along a first direction; a second lens piece, configured It is above the first ridge and includes a plurality of second ridges, wherein a second vertex of each of the second ridges faces the light guide element, and each of the second ridges is along a first Extending in two directions, and the angle between the second direction and the first direction is greater than 75° and less than 105°; and a third ridge is arranged above the second ridge and includes a plurality of third ridges, wherein A third vertex angle of each of the third ridges faces away from the light guide element direction, and each of the third lenses extends along a third direction, and the angle between the third direction and the first direction is less than 15°, wherein the first lens piece, the second lens piece and the The third vertex plate satisfies 160°≦θ1+θ3≦200°, θ2<θ1 and θ2<θ3, and 56°≦θ2≦62°, where θ1 is the angle size of the first vertex angle and θ2 is the second vertex angle. The angle size of the angle, and θ3 is the angle size of the third vertex angle. A backlight module includes: a light source for emitting an illumination beam; a light guide element disposed on the transmission path of the illumination beam; a first optical film disposed on the light guide element and including a plurality of A first lens, in which a first vertex angle of each of the first lenses faces the light guide element, and each of the first lenses extends along a first direction; a second lens piece, configured It is above the first ridge and includes a plurality of second ridges, wherein a second vertex of each of the second ridges faces the light guide element, and each of the second ridges is along a first Extending in two directions, and the angle between the second direction and the first direction is greater than 75° and less than 105°; and a third ridge is arranged above the second ridge and includes a plurality of third ridges, wherein A third vertex angle of each of the third ridges faces a direction away from the light guide element, and each of the third ridges extends along a third direction, and the third direction is consistent with the first direction. The included angle is less than 15°, wherein the surface of the second fiber sheet facing the third fiber sheet has an anti-adsorption microstructure. A backlight module includes: a light source for emitting an illumination beam; A light guide element is arranged on the transmission path of the illumination beam; a first lens piece is arranged on the light guide element and includes a plurality of first lens elements, wherein a first lens element of each of the first lens elements is provided. A vertex faces the light guide element, and each of the first ridges extends along a first direction; a second ridge is disposed above the first ridge and includes a plurality of second ridges, A second vertex angle of each of the second ridges faces the light guide element, each of the second ridges extends along a second direction, and the angle between the second direction and the first direction is greater than 75° and less than 105°; a third flange piece is arranged above the second flange piece and includes a plurality of third flanges, wherein a third vertex angle of each of the third flanges faces away from the guide The direction of the optical element, and each of the third lenses extends along a third direction, and the angle between the third direction and the first direction is less than 15°; and a diffuser or a reflective polarizing brightness enhancement film , disposed above the third piece. A backlight module includes: a light source for emitting an illumination beam; a light guide element disposed on the transmission path of the illumination beam; a first optical film disposed on the light guide element and including a plurality of A first lens, in which a first vertex angle of each of the first lenses faces the light guide element, and each of the first lenses extends along a first direction; a second lens piece, configured It is above the first ridge and includes a plurality of second ridges, wherein a second vertex of each of the second ridges faces the light guide element, and each of the second ridges is along a first extends in two directions, and the second direction and the first direction The angle between the two directions is greater than 75° and less than 105°; and a third pane is arranged above the second pane and includes a plurality of third panes, wherein each of the third panes has a third top The angle is oriented away from the light guide element, and each of the third lenses extends along a third direction, and the angle between the third direction and the first direction is less than 15°, wherein each of the first The ridge line formed by the first vertex corner of the ridge, the ridge line formed by the second vertex corner of each of the second ridges, and the third vertex corner of each of the third ridges. The ridges are curves or polylines respectively. A display device includes: a backlight module, including: a light source for emitting an illumination beam; a light guide element disposed on the transmission path of the illumination beam; and a first film disposed on the light guide element on, and including a plurality of first ridges, wherein a first vertex angle of each of the first ridges faces the light guide element, and each of the first ridges extends along a first direction; The second lens is disposed above the first lens and includes a plurality of second lenses, wherein a second vertex angle of each of the second lenses faces the light guide element, and each of the second lenses The haze extends along a second direction, and the angle between the second direction and the first direction is greater than 75° and less than 105°, wherein the haze of the second haze sheet is greater than 0% and less than or equal to 50%; and A third rim piece is disposed above the second ridge piece and includes a plurality of third ridges, wherein a third vertex of each of the third ridges faces away from the the direction of the light guide element, and each of the third lenses extends along a third direction, and the angle between the third direction and the first direction is less than 15°; and a display panel is provided on the backlight module above.