Light diffusion plate, display device and backlight module of head-up display device

Abstract

A light diffusion plate suitable for a display device comprises a first transparent layer and a diffusion layer, the diffusion layer comprises a plurality of first diffusion particles dispersed therein, the diffusion layer is located above the first transparent layer, the first transparent layer is arranged between a light-emitting element of the display device and the diffusion layer, and the refractive index of the first transparent layer is larger than that of the diffusion layer. The invention also provides a display device and a backlight module of a head-up display device.

Description

Technical Field

[0001] This invention relates to a light diffusion plate, a display device, and a backlight module for a head-up display device. Background Technology

[0002] In head-up display (HUD) applications, the displayed content is typically presented against a black background with a small number of icons. Therefore, the brightness performance of a single light source (such as a single light-emitting diode) when partially illuminated is particularly crucial. To evaluate the effect of partial illumination, the industry commonly uses the one-zone ratio (OZR) as a metric. This metric is defined as the percentage of luminance of a single emitting area corresponding to a single illuminated LED, compared to the luminance of that single emitting area when all LEDs are illuminated simultaneously. Therefore, a higher one-zone ratio indicates that the light emitted by a single LED is more concentrated and less likely to be guided or scattered to adjacent emitting areas, which helps improve the contrast and clarity of local icons and enhances photoelectric conversion efficiency.

[0003] In known backlight modules, a diffuser plate is placed above the light source. Generally, thinning the diffuser plate can improve the brightness of the backlight module. However, thinning the diffuser plate reduces its mechanical strength, increasing the risk of breakage. Furthermore, changing the thickness of the diffuser plate can lead to issues with bright and dark banding, which usually requires adjusting the position of the supporting components. However, adjusting the position of these components consumes a significant amount of experimental time. Additionally, if total internal reflection occurs in the diffuser plate, it can cause light to propagate laterally within the diffuser, thereby reducing the brightness ratio of individual areas. Therefore, a method to improve these problems is urgently needed. Summary of the Invention

[0004] This invention provides a light diffusion plate, a display device, and a backlight module for a head-up display device, which can improve hot spot problems and / or bright and dark patterns.

[0005] At least one embodiment of the present invention provides a light diffusion plate suitable for a display device, including a first transparent layer and a diffusion layer. The diffusion layer contains a plurality of first diffusion particles dispersed therein. The diffusion layer is located above the first transparent layer. The first transparent layer is disposed between the light-emitting element of the display device and the diffusion layer. The refractive index of the first transparent layer is greater than the refractive index of the diffusion layer.

[0006] In one embodiment of the light diffusion plate described above, the thickness of the first transparent layer is greater than the thickness of the diffusion layer.

[0007] In one embodiment of the light diffusion plate described above, the first transparent layer contacts the diffusion layer, and the first transparent layer and the diffusion layer are integrally formed.

[0008] In one embodiment of the light diffusion plate described above, the surface of the first transparent layer and / or the surface of the diffusion layer includes a plurality of diffusion microstructures.

[0009] In one embodiment of the light diffusion plate described above, the first transparent layer contains a plurality of second diffusion particles dispersed therein, wherein the haze value of the diffusion layer is greater than the haze value of the first transparent layer.

[0010] In one embodiment of the light diffusion plate described above, it further includes:

[0011] A second transparent layer, wherein the diffusion layer is located between the first transparent layer and the second transparent layer.

[0012] At least one embodiment of the present invention provides a display device, including a circuit board, a plurality of light-emitting elements and a light diffusion plate. The plurality of light-emitting elements are disposed above the circuit board. The light diffusion plate includes a first transparent layer and a diffusion layer. The diffusion layer contains a plurality of first diffusion particles dispersed therein. The diffusion layer is located above the first transparent layer. The first transparent layer is located between the light-emitting elements and the diffusion layer. The refractive index of the first transparent layer is greater than the refractive index of the diffusion layer.

[0013] In one embodiment of the above-mentioned display device, the vertical distance from the interface between the first transparent layer and the diffusion layer to the top surface of the plurality of light-emitting elements is T3, and the spacing between the plurality of light-emitting elements is P, wherein T3 falls between 1.067 times P and 1.133 times P.

[0014] In one embodiment of the above-described display device, it further includes:

[0015] An optical thin film is disposed between the first transparent layer and the diffusion layer.

[0016] In one embodiment of the above-described display device, it further includes:

[0017] A light control film, wherein the light control film includes at least one of a reflective polarizing brightening film and a brightening film, and the light diffuser is located between the light control film and the plurality of light-emitting elements.

[0018] In one embodiment of the above-described display device, the first transparent layer contacts the diffusion layer, and the first transparent layer and the diffusion layer are integrally formed.

[0019] In one embodiment of the above-described display device, it further includes:

[0020] A liquid crystal panel, wherein the light diffuser is located between the liquid crystal panel and the plurality of light-emitting elements.

[0021] At least one embodiment of the present invention provides a backlight module for a head-up display device, including a circuit board, a plurality of light-emitting elements and a light diffusion plate. The plurality of light-emitting elements are disposed above the circuit board. The light diffusion plate includes a first transparent layer and a diffusion layer. The diffusion layer contains a plurality of first diffusion particles dispersed therein. The diffusion layer is located above the first transparent layer. The first transparent layer is located between the light-emitting elements and the diffusion layer. The refractive index of the first transparent layer is greater than the refractive index of the diffusion layer. Attached Figure Description

[0022] Figure 1 This is a cross-sectional schematic diagram of a light diffusion plate according to an embodiment of the present invention.

[0023] Figures 2A to 2C This is a cross-sectional schematic diagram of a light diffusion plate illustrated according to some embodiments of the present invention.

[0024] Figures 3A to 3C This is a cross-sectional schematic diagram of a light diffusion plate illustrated according to some embodiments of the present invention.

[0025] Figure 4 This is a cross-sectional schematic diagram of a light diffusion plate according to an embodiment of the present invention.

[0026] Figure 5 This is a cross-sectional schematic diagram of a light diffusion plate according to an embodiment of the present invention.

[0027] Figure 6 This is a cross-sectional schematic diagram of a backlight module of a display device according to an embodiment of the present invention.

[0028] Figure 7 These are top views and cross-sectional views of a light-emitting element and a barrier structure according to an embodiment of the present invention.

[0029] Figure 8A This is a cross-sectional schematic diagram simulating a light-emitting element according to an embodiment of the present invention.

[0030] Figures 8B to 8E It is a change Figure 8A The brightness distribution of a single light-emitting element is obtained on the simulation plane after determining the distance between the light-emitting element and the simulation plane.

[0031] Figure 9A This is a cross-sectional schematic diagram simulating a light-emitting element according to an embodiment of the present invention.

[0032] Figures 9B to 9H It is a change Figure 9A The brightness distribution of a single light-emitting element is obtained on the simulation plane after determining the distance between the light-emitting element and the simulation plane.

[0033] Figure 10This is a cross-sectional schematic diagram of a backlight module of a display device according to an embodiment of the present invention.

[0034] Figure 11 This is a cross-sectional schematic diagram of a backlight module of a display device according to an embodiment of the present invention.

[0035] Figure 12 This is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0036] In the attached figures, the following labels are used:

[0037] 1: Display device

[0038] 10, 10A, 10B, 10C: Backlight Module

[0039] 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J, 100K: Light diffusion plates

[0040] 110: First transparent layer

[0041] 110a, 120a, 140a: First face

[0042] 110b, 120b, 140b: Second side

[0043] 112: Second Diffused Particle

[0044] 120: Diffusion layer

[0045] 122: First Diffused Particle

[0046] 130a, 130b, 130c: Diffusion microstructures

[0047] 140: Second transparent layer

[0048] 150: Optical thin film

[0049] 200: Plain plate

[0050] 210: Circuit board

[0051] 220: Light-emitting element

[0052] 230: Retaining wall structure

[0053] 310, 320, 330: Light control film

[0054] 400: LCD panel

[0055] 410: First substrate

[0056] 420: Second substrate

[0057] 430: First polarizer

[0058] 440: Second polarizer

[0059] AG: Air gap

[0060] D1: First Direction

[0061] D2: Second Direction

[0062] DM: Dark Pattern

[0063] DP: Simulation plane

[0064] H,T0,T3,Z: Distance

[0065] L: Light

[0066] LM: Glossy Texture

[0067] O: Opening

[0068] P: Spacing

[0069] S1, S2: Trapezoidal structure

[0070] T, T1, T2, T4: Thickness

[0071] W: Width Detailed Implementation

[0072] Figure 1 This is a cross-sectional schematic diagram of a light diffusion plate 100A according to an embodiment of the present invention. Please refer to... Figure 1 The light diffusion plate 100A includes a first transparent layer 110 and a diffusion layer 120. The diffusion layer 120 is located above the first transparent layer 110. In some embodiments, the first transparent layer 110 contacts the diffusion layer 120, and the first transparent layer 110 and the diffusion layer 120 are integrally formed. For example, the first transparent layer 110 and the diffusion layer 120 are integrally formed using a co-pressing method.

[0073] In some embodiments, the substrate of the first transparent layer 110 includes polyimide (PI), polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (PES), polymethylmethacrylate (PMMA), polycarbonate (PC), polyurethane (PU), or other suitable materials. Furthermore, to increase the refractive index, a metal oxide, such as magnesium oxide (MgO2), may be doped into the substrate. In some embodiments, the refractive index of the first transparent layer 110 is 1.49 to 1.68.

[0074] In some embodiments, the substrate of the diffusion layer 120 includes polyimide (PI), polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (PES), polymethylmethacrylate (PMMA), polycarbonate (PC), polyurethane (PU), or other suitable materials. Furthermore, to increase the refractive index, metal oxides, such as magnesium oxide (MgO2), may be doped into the substrate. In some embodiments, the substrate of the diffusion layer 120 may be the same as or different from that of the first transparent layer 110.

[0075] In some embodiments, the diffusion layer 120 includes a plurality of first diffusion particles 122 dispersed therein. Specifically, the diffusion layer 120 includes first diffusion particles 122 dispersed in a polymer substrate to increase the refractive index of the diffusion layer 120. In some embodiments, the material of the first diffusion particles 122 includes metal oxides (e.g., titanium oxide, magnesium oxide (MgO2), silicon oxide, or other suitable materials). In some embodiments, the refractive index of the diffusion layer 120 can be adjusted by doping the first diffusion particles 122. Even if the diffusion layer 120 and the first transparent layer 110 contain the same substrate, the addition of the first diffusion particles 122 can still make the refractive index of the diffusion layer 120 lower than that of the first transparent layer 110.

[0076] The first transparent layer 110 is configured to be disposed between the light-emitting element of the display device and the diffusion layer 120. Therefore, the light L emitted by the light-emitting element of the display device first enters the first transparent layer 110 from its first surface 110a. Then, the light L exits the first transparent layer 110 from its second surface 110b and enters the diffusion layer 120 via its first surface 120a. Finally, it exits the diffusion layer 120 from its second surface 120b.

[0077] In this embodiment, the refractive index of the first transparent layer 110 is greater than that of the diffusion layer 120. Therefore, this helps to ensure that the total internal reflection of light L mainly occurs in the first transparent layer 110 rather than in the diffusion layer 120. Due to the simple structure of the first transparent layer 110, the total internal reflection of light L in the first transparent layer 110 can be easily controlled by adjusting the first transparent layer 110. Reducing the optical path length of the total internal reflection of light L in the first transparent layer 110 helps to improve the octave ratio (OZR). Specifically, reducing the optical path length of total internal reflection helps to prevent light emitted from a single light-emitting element in the display device from reaching the position of adjacent light-emitting elements. In other words, the octave ratio can be improved by reducing the lateral distance H that light L travels in the first transparent layer 110.

[0078] Figures 2A to 2C These are schematic cross-sectional views of light diffusion plates 100B, 100C, and 100D, drawn according to some embodiments of the present invention. It must be noted that... Figures 2A to 2C The embodiments follow Figure 1 The component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0079] exist Figures 2A to 2CIn some embodiments, the surface of the first transparent layer 110 and / or the surface of the diffusion layer 120 include a plurality of diffusion microstructures 130a. For example, in Figure 2A In the light diffusion plate 100B, the first surface 110a of the first transparent layer 110 includes a diffusion microstructure 130a. In this embodiment, the diffusion microstructure 130a is embedded in the first surface 110a in a particle-like manner, but this is not a limitation. For example, the diffusion microstructure can be formed on the first surface 110a by sandblasting or chemical etching, or by UV imprinting. As long as light can diffuse after passing through the diffusion microstructure, the effect of the present invention can be achieved. Figure 2B In the light diffusion plate 100C, diffusion microstructures 130a are included on the second surface 110b of the first transparent layer 110 and the first surface 120a of the diffusion layer 120. The diffusion microstructures 130a are embedded in the second surface 110b and the first surface 120a in a particle-like manner. Figure 2C In the light diffusion plate 100D, the first surface 110a and the second surface 110b of the first transparent layer 110 and the first surface 120a and the second surface 120b of the diffusion layer 120 both contain diffusion microstructures 130a. The diffusion microstructures 130a are embedded in the first surface 110a and the second surface 110b of the first transparent layer 110 and the first surface 120a and the second surface 120b of the diffusion layer 120 in a particle-like manner.

[0080] By setting the diffusion microstructure 130a, the direction of light L can be changed, thereby disrupting total internal reflection of light L. Therefore, the brightness ratio of a single area can be improved.

[0081] Figures 3A to 3C These are schematic cross-sectional views of light diffusion plates 100E, 100F, and 100G, drawn according to some embodiments of the present invention. It must be noted that... Figures 3A to 3C The embodiments follow Figure 1 The component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0082] exist Figures 3A to 3C In some embodiments, the surface of the first transparent layer 110 and / or the surface of the diffusion layer 120 include a plurality of diffusion microstructures 130b. For example, in Figure 3A In the light diffusion plate 100E, a diffusion microstructure 130b is included on the first surface 110a of the first transparent layer 110. The diffusion microstructure 130b is formed on the first surface 110a by imprinting, photolithography, or other suitable methods. Figure 3BIn the light diffusion plate 100F, a diffusion microstructure 130b is included on the second surface 110b of the first transparent layer 110 and the first surface 120a of the diffusion layer 120. The diffusion microstructure 130b is formed on the second surface 110b or the first surface 120a by imprinting, photolithography, or other suitable methods. Figure 3C In the light diffusion plate 100G, the first surface 110a and the second surface 110b of the first transparent layer 110 and the first surface 120a and the second surface 120b of the diffusion layer 120 both contain diffusion microstructures 130b. The diffusion microstructures 130b are formed on the first surface 110a and the second surface 110b of the first transparent layer 110 and the first surface 120a and the second surface 120b of the diffusion layer 120 by imprinting, photolithography or other suitable methods.

[0083] In some embodiments, the diffusion microstructure 130b includes a pyramid-shaped microstructure or other structures that are beneficial for changing the direction of light L.

[0084] By setting the diffusion microstructure 130b, the direction of light L can be changed, thereby disrupting total internal reflection of light L. Therefore, the brightness ratio of a single area can be improved.

[0085] Figure 4 This is a schematic cross-sectional view of a light diffusion plate 100H according to an embodiment of the present invention. It must be noted here that... Figure 4 The embodiments follow Figure 1 The component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0086] exist Figure 4 In one embodiment, the surface of the first transparent layer 110 includes a plurality of diffused microstructures 130c. For example, in Figure 4 In the light diffusion plate 100H, a diffusion microstructure 130c is included on the first surface 110a of the first transparent layer 110. The diffusion microstructure 130c is formed on the first surface 110a by sandblasting, etching or other suitable methods. In some embodiments, the diffusion microstructure 130c may also be included on the second surface 120b of the diffusion layer 120.

[0087] By setting the diffusion microstructure 130c, the direction of light L can be changed, thereby disrupting total internal reflection of light L. Therefore, the brightness ratio of a single area can be improved.

[0088] Figure 5 This is a schematic cross-sectional view of a light diffusion plate 100I according to an embodiment of the present invention. It must be noted here that... Figure 5 The embodiments follow Figure 2CThe component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0089] exist Figure 5 In the light diffusion plate 100I, not only does the diffusion layer 120 contain first diffusing particles 122, but the first transparent layer 110 also contains a plurality of second diffusing particles 112 dispersed therein to improve the refractive index of the first transparent layer 110. The doping concentration of the first diffusing particles 122 in the diffusion layer 120 is greater than the doping concentration of the second diffusing particles 112 in the first transparent layer 110. For example, the haze value of the diffusion layer 120 is greater than the haze value of the first transparent layer 110. In some embodiments, the material of the second diffusing particles 112 includes metal oxides (e.g., titanium oxide, magnesium oxide (MgO2), etc.), silicon oxide, or other suitable materials. The haze value is affected by the refractive index (n), extinction coefficient (k), shape, and Gaussian distribution of the particle size. In some embodiments, the haze value of the first transparent layer 110 is 0% to 5%, and the haze value of the diffusion layer 120 is greater than 20%.

[0090] Figure 6 This is a cross-sectional schematic diagram of a backlight module 10A of a display device according to an embodiment of the present invention. Please refer to... Figure 6 The backlight module 10A of the display device includes a light plate 200 and a light diffusion plate 100D. In this embodiment, the light diffusion plate 100D is used as an example for description, but this disclosure is not limited thereto. Figure 6 The light diffusion plate 100D can be used as described above. Figures 1 to 5 The light diffuser plate in any of the embodiments is replaced.

[0091] Please refer to Figure 6 The light-emitting plate 200 includes a circuit board 210, a plurality of light-emitting elements 220, and a barrier structure 230. The light-emitting elements 220 and the barrier structure 230 are disposed above the circuit board 210. The light-emitting elements 220 are bonded to the circuit board 210 and arranged in an array on the circuit board 210. The light-emitting elements 220 are, for example, light-emitting diodes or other light-emitting elements. The barrier structure 230 is laterally located between the light-emitting elements 220. The barrier structure 230 is used to reflect the light emitted by the light-emitting elements 220, thereby reducing mutual interference between the light emitted by different light-emitting elements 220.

[0092] In this embodiment, an air gap AG is included between the light plate 200 and the light diffusion plate 100D. The refractive index of the air gap AG is less than the refractive index of the first transparent layer 110.

[0093] In some embodiments, distance T3 may also be referred to as the vertical distance from the interface between the first transparent layer 110 and the diffusion layer 120 to the top surface of the light-emitting element 220. In some embodiments, the interface between the first transparent layer 110 and the diffusion layer 120 is located on the light-diffusing surface of the backlight module.

[0094] In this embodiment, distance T3 is essentially equal to distance T0 plus the thickness T1 of the first transparent layer 110. In other words, distance T3 can be controlled by adjusting the thickness T1 of the first transparent layer 110. In this embodiment, the light diffuser 100D is fixed to the mechanism 510. The mechanism 510 determines the distance between the light diffuser 100D and the light-emitting element 220 of the light plate 200. In this embodiment, distance T3 can be changed by adjusting the thickness T1 of the first transparent layer 110 without changing the position of the mechanism 510 of the backlight module 10A. Therefore, the experimental time required for adjusting the position of the mechanism 510 can be saved.

[0095] In some embodiments, reducing the thickness T1 of the first transparent layer 110 helps to reduce the distance that light L travels laterally within the first transparent layer 110. For example, it is known that a total thickness (thickness T1 plus thickness T2) of 1.2 mm is sufficient to provide adequate rigidity to prevent the liquid crystal panel 400 (see reference) located thereon from being too rigid. Figure 12 ) fragments. To obtain a larger OZR, a smaller thickness T1 (e.g., 0.2 mm) can be used in combination with a larger thickness T2 (e.g., 1.0 mm).

[0096] Figure 7 These are top views and cross-sectional views illustrating a light-emitting element and a barrier structure according to an embodiment of the present invention. Please refer to... Figure 7 The barrier structure 230 is, for example, lattice-shaped, and the light-emitting element 220 is disposed in the opening O of the barrier structure 230. In some embodiments, the light-emitting element 220 is arranged in an array along a first direction D1 and a second direction D2, wherein the first direction D1 is perpendicular to the second direction D2.

[0097] Figure 8A This is a cross-sectional schematic diagram simulating the light-emitting element 220 according to an embodiment of the present invention. Figures 8B to 8E It is a change Figure 8A The brightness distribution map corresponding to one of the light-emitting elements is obtained on the simulation plane DP after determining the distance Z between the light-emitting element 220 and the simulation plane DP. Figures 8B to 8E In the simulation, the spacing P of the light-emitting elements 220 is 7.5 mm. Figures 8B to 8E In the simulation, the distances Z between the light-emitting element 220 and the simulation plane DP are 6.5mm, 7mm, 7.5mm and 8mm, respectively.

[0098] Simulation results show that when the distance Z between the light-emitting element 220 and the simulation plane DP is greater than or equal to 7.5 mm, the hot spot problem can be significantly improved. In other words, the distance Z between the light-emitting element 220 and the simulation plane DP is preferably greater than or equal to the spacing P. If the aforementioned simulation results are applied to... Figure 6 In the displayed display device (assuming there is no barrier structure between the light-emitting elements), a distance T3 greater than or equal to the spacing P can improve the hot spot problem.

[0099] Figure 9A This is a cross-sectional schematic diagram simulating a light-emitting element according to an embodiment of the present invention. Figures 9B to 9H It is a change Figure 9A The brightness distribution map corresponding to one of the light-emitting elements is obtained on the simulation plane after determining the distance Z between the light-emitting element and the simulation plane DP. Figures 9B to 9H In the simulation, the spacing P of the light-emitting elements 220 is 7.5mm, the height of the barrier structure 230 is 7mm, and the width W of the bottom surface of the opening O of the barrier structure 230 is 3.4758mm. Figures 9B to 9H In the simulation, the distances Z between the light-emitting element 220 and the simulation plane DP are 7mm, 7.5mm, 8mm, 8.25mm, 8.5mm, 8.75mm and 9mm respectively.

[0100] Depend on Figures 9B to 9C It can be seen that when the distance Z is 7mm and 7.5mm, obvious dark lines DM appear on the simulated plane DP. These dark lines DM correspond to the position of the retaining wall structure 230. On the other hand, from Figures 9G to 9H It can be seen that when the distance Z is 8.75mm and 9mm, obvious bright fringes LM appear on the simulated plane DP. These bright fringes LM correspond to the positions of the retaining wall structure 230. Therefore, in order to reduce the bright or dark fringes generated by the retaining wall structure 230, the distance Z is preferably controlled within the range of 8mm and 8.5mm, that is, the distance Z preferably falls between 1.067 times the spacing P and 1.133 times the spacing P. If the above simulation results are applied to... Figure 6 In the displayed device, a distance T3 falling between 1.067 times the pitch P and 1.133 times the pitch P can reduce the problem of bright or dark lines. For example, the distance T3 is controlled within the range of 8mm and 8.5mm.

[0101] In embodiments of the present invention, the distance T3 can be changed by adjusting the thickness T1 of the first transparent layer 110 without changing the structure of the backlight module. Therefore, the hot spot problem or bright / dark pattern problem of the backlight module can be easily improved.

[0102] Table 1 provides various configurations of the backlight module of the display device according to the first embodiment of the present invention and the brightness ratio of a single zone.

[0103] Table 1

[0104]

[0105]

[0106] Table 2 provides various configurations of the backlight module of the display device according to the second embodiment of the present invention and the brightness ratio of a single zone.

[0107] Table 2

[0108]

[0109] Table 3 provides various configurations of the backlight module of the display device according to the third embodiment of the present invention and the brightness ratio of a single zone.

[0110] Table 3

[0111]

[0112]

[0113] Tables 1 to 3 show that a single-area luminance ratio greater than 33% can be achieved when the distance T3 falls within the range of 1.067 times the spacing P to 1.133 times the spacing P.

[0114] Figure 10 This is a cross-sectional schematic diagram of a backlight module 10B of a display device according to an embodiment of the present invention. It should be noted that... Figure 10 The embodiments follow Figure 6 The component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0115] Please refer to Figure 10 In this embodiment, the backlight module 10B of the display device includes a light plate 200 and a light diffusion plate 100J. In this embodiment, the light diffusion plate 100J includes a first transparent layer 110 and a diffusion layer 120, as well as a second transparent layer 140. The diffusion layer 120 is located between the first transparent layer 110 and the second transparent layer 140. In some embodiments, the first transparent layer 110 and the second transparent layer 140 comprise the same material.

[0116] In some embodiments, the first surface 140a of the second transparent layer 140 contacts the second surface 120b of the diffusion layer 120. In some embodiments, the first transparent layer 110, the diffusion layer 120, and the second transparent layer 140 are integrally formed. For example, the first transparent layer 110, the diffusion layer 120, and the second transparent layer 140 are integrally formed using a co-molding method.

[0117] In some embodiments, the surfaces of the first transparent layer 110, the diffusion layer 120, and / or the second transparent layer 140 include a plurality of diffusion microstructures 130a. For example, the first surface 110a of the first transparent layer 110, the second surface 120b of the diffusion layer 120, the first surface 140a of the second transparent layer 140, and the second surface 140b of the second transparent layer 140 have diffusion microstructures 130a. Other types of diffusion microstructures (see [reference]). Figures 3A to 4 It can also be applied to the light diffusion plate 100J.

[0118] In this embodiment, the sum of the thickness T1 of the first transparent layer 110, the thickness T2 of the diffusion layer 120, and the thickness T4 of the second transparent layer 140 is 1.0 mm to 1.2 mm. In some embodiments, the addition of the second transparent layer 140 reduces the thickness T2 of the diffusion layer 120, thereby maintaining the total thickness and structural strength (e.g., rigidity) of the light diffusion plate 100J. In this embodiment, the brightness of the backlight module can be improved by the provision of the second transparent layer 140.

[0119] Figure 11 This is a cross-sectional schematic diagram of a backlight module 10C of a display device according to an embodiment of the present invention. It should be noted that... Figure 11 The embodiments follow Figure 6 The component reference numerals and partial content of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0120] Please refer to Figure 11In this embodiment, the backlight module 10C of the display device includes a light plate 200, a light diffuser plate 100K, and light control films 310, 320, and 330. In this embodiment, the light diffuser plate 100K includes a first transparent layer 110 and a diffuser layer 120, as well as an optical film 150. The optical film 150 is disposed between the first transparent layer 110 and the diffuser layer 120. The optical film 150 is, for example, a dual brightness enhancement film (DBEF) or other suitable optical films. In this embodiment, the optical film 150 has a multilayer structure, but this disclosure is not limited thereto. In other embodiments, the optical film 150 has a single-layer structure.

[0121] In this embodiment, the light control films 310, 320, and 330 above the light diffuser 100K include at least one of a reflective polarizing brightness enhancement film and a brightness enhancement film (BEF). For example, the light control films 310 and 320 are brightness enhancement films (e.g., prism films), while the light control film 330 is a reflective polarizing brightness enhancement film. The light diffuser 100K is located between the light control films 310, 320, and 330 and the light-emitting element 220.

[0122] In some embodiments, both the light control film 330 and the optical film 150 are reflective polarizing brightness enhancement films. When the light L emitted by the light-emitting element 220 reaches the light control film 330, part of the light L passes through the light control film 330, while the other part is reflected by the light control film 330. The optical film 150 disposed in the light diffuser plate 100K can reflect the light L previously reflected by the light control film 330 again, thereby enhancing the brightness of the backlight module 10C. In some embodiments, the transmission axes of the light control film 330 and the optical film 150 are parallel to each other.

[0123] Figure 12 This is a cross-sectional schematic diagram of a display device 1 according to an embodiment of the present invention. Please refer to... Figure 12 The display device 1 includes a backlight module 10 and an LCD panel 400.

[0124] The backlight module 10 includes a light plate 200 and a light diffusion plate 100. In this embodiment, the light diffusion plate 100 includes a first transparent layer and a diffusion layer. Figure 12 The light diffusion plate 100 can be the light diffusion plate in any of the foregoing embodiments.

[0125] A liquid crystal panel 400 is superimposed on a backlight module 10. A light diffuser 100 is located between the liquid crystal panel 400 and the light-emitting element 220. The liquid crystal panel 400 includes a first substrate 410, a second substrate 420, a first polarizer 430, and a second polarizer 440. A liquid crystal layer (not shown) is disposed between the first substrate 410 and the second substrate 420. The first polarizer 430 and the second polarizer 440 are respectively disposed on the first substrate 410 and the second substrate 420.

[0126] The rigidity of the light diffuser plate 100 is affected by its thickness T. Insufficient thickness T of the light diffuser plate 100 will make it difficult to provide support for other optical structures (such as the first substrate 410, the second substrate 420, or the liquid crystal layer between them).

[0127] In summary, without altering the structural components of the backlight module, the distance between the diffuser layer and the light-emitting element can be changed by adjusting the thickness of the first transparent layer. Therefore, hot spot issues or bright / dark ripple problems in the backlight module can be easily improved. Furthermore, the total internal reflection of light within the first transparent layer can be easily controlled by adjusting it, thereby improving the brightness ratio of a single area.

Claims

1. A light diffusion plate suitable for display devices, characterized in that, include: First transparent layer; as well as A diffusion layer comprising a plurality of first diffusion particles dispersed therein and located above a first transparent layer, wherein the first transparent layer is disposed between a light-emitting element of the display device and the diffusion layer, and the refractive index of the first transparent layer is greater than the refractive index of the diffusion layer.

2. The light diffusion plate as described in claim 1, characterized in that, The thickness of the first transparent layer is greater than the thickness of the diffusion layer.

3. The light diffusion plate as described in claim 1, characterized in that, The first transparent layer contacts the diffusion layer, and the first transparent layer and the diffusion layer are integrally formed.

4. The light diffusion plate as described in claim 1, characterized in that, The surface of the first transparent layer and / or the surface of the diffusion layer includes multiple diffusion microstructures.

5. The light diffusion plate as described in claim 1, characterized in that, The first transparent layer contains a plurality of second diffusing particles dispersed therein, wherein the haze value of the diffusing layer is greater than the haze value of the first transparent layer.

6. The light diffusion plate as described in claim 1, characterized in that, Also includes: A second transparent layer, wherein the diffusion layer is located between the first transparent layer and the second transparent layer.

7. A display device, characterized in that, include: A circuit board; Multiple light-emitting elements are arranged above the circuit board; as well as A light diffuser plate, comprising: First transparent layer; as well as A diffusion layer comprising a plurality of first diffusion particles dispersed therein and located above a first transparent layer, wherein the first transparent layer is located between the plurality of light-emitting elements and the diffusion layer, and the refractive index of the first transparent layer is greater than the refractive index of the diffusion layer.

8. The display device as claimed in claim 7, characterized in that, The vertical distance from the interface between the first transparent layer and the diffusion layer to the top surface of the plurality of light-emitting elements is T3, and the spacing between the plurality of light-emitting elements is P, wherein T3 falls between 1.067 times P and 1.133 times P.

9. The display device as claimed in claim 7, characterized in that, Also includes: An optical thin film is disposed between the first transparent layer and the diffusion layer.

10. The display device as claimed in claim 7, characterized in that, Also includes: A light control film, wherein the light control film includes at least one of a reflective polarizing brightening film and a brightening film, and the light diffuser is located between the light control film and the plurality of light-emitting elements.

11. The display device as claimed in claim 7, characterized in that, The first transparent layer contacts the diffusion layer, and the first transparent layer and the diffusion layer are integrally formed.

12. The display device as claimed in claim 7, characterized in that, Also includes: A liquid crystal panel, wherein the light diffuser is located between the liquid crystal panel and the plurality of light-emitting elements.

13. A backlight module for a head-up display device, characterized in that, include: A circuit board; Multiple light-emitting elements are arranged above the circuit board; as well as A light diffuser plate, comprising: First transparent layer; as well as A diffusion layer comprising a plurality of first diffusion particles dispersed therein and located above a first transparent layer, wherein the first transparent layer is located between the plurality of light-emitting elements and the diffusion layer, and the refractive index of the first transparent layer is greater than the refractive index of the diffusion layer.

Images