Light guide plate and backlight module thereof

Abstract

The light guide plate is provided with a light incidence side face, an upper surface and a lower surface, the upper surface and the lower surface are oppositely arranged, and the upper surface and the lower surface are adjacent to the light incidence side face. The upper surface or the lower surface is provided with a plurality of concave lattice point structures, each lattice point structure is provided with a light-receiving surface and a backlight surface, and in a cross section perpendicular to the upper surface, the lower surface and the light incident side surface, the included angle between the line segment of the light-receiving surface and the vertical line is 50-60 degrees, and the included angle between the line segment of the backlight surface and the vertical line is 30-50 degrees; an included angle between a reference surface extending from a connecting line of any two points of the edge line of the backlight surface and the backlight surface is 10-30 degrees; the backlight module comprises the light guide plate and an LED light bar correspondingly arranged on the light incident side face of the light guide plate. Through the structural angle configuration of the lattice point structure, the light-emitting brightness performance can be effectively improved, and the whole backlight module has high light-emitting brightness and light utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of optical module technology, and in particular to a light guide plate and its backlight module. Background Technology

[0002] In existing technologies, light guide plates are used to guide and uniformly distribute light onto a target surface. Their main applications include liquid crystal display (LCD) backlight modules, advertising displays, and other optical display devices. Current light guide plates typically control the emission characteristics of light through various optical design techniques to achieve uniform light output and efficient light utilization. However, with increasingly stringent requirements for brightness, light uniformity, and energy efficiency in display products, light guide plate design faces even greater challenges.

[0003] In practical applications, light guide plate design must consider numerous factors, including how to balance light uniformity, output brightness, luminous efficiency, and manufacturing feasibility. Different application scenarios have varying requirements for light output characteristics, size specifications, and processing precision, necessitating an optimal balance among these multiple conditions in light guide plate design. Therefore, how to improve the output brightness and light uniformity of light guide plates while maintaining structural manufacturability and reasonable cost remains a pressing technological challenge.

[0004] In view of this, based on the applicant’s extensive experience in optical module design and application, the applicant has conceived and proposed a light guide plate and its backlight module to overcome the problems existing in the prior art. Summary of the Invention

[0005] One of the objectives of this invention is to provide a light guide plate and its backlight module, which, by setting a dot structure with a specific angle configuration on the light guide plate, allows the light inside the light guide plate to be guided and adjusted during the emission process, thereby improving the light emission behavior and helping to enhance the overall light utilization performance.

[0006] To achieve the above objectives, one embodiment of the present invention discloses a light guide plate having a light-incident side, an upper surface, and a lower surface. The upper surface and the lower surface are arranged opposite to each other and are respectively adjacent to the light-incident side. The light guide plate is characterized in that: the upper surface or the lower surface of the light guide plate has a plurality of dot structures, each dot structure being a concave structure and having a light-facing surface and a backlight surface. In a cross-section where each dot structure is perpendicular to both the upper and lower surfaces and perpendicular to the light-incident side, the angle between the first line segment formed by the light-facing surface and the vertical line is 50-60 degrees, and the angle between the second line segment formed by the backlight surface and the vertical line is 30-50 degrees. Furthermore, the angle between the reference plane perpendicularly extending from the line connecting any two points on the edge of the backlight surface and the backlight surface is 10-30 degrees. This allows the light to achieve better guidance and emission effects on the light guide plate, thereby improving the light output brightness of the light guide plate and enhancing the overall light utilization efficiency.

[0007] In another embodiment, the depth of each of the halftone dot structures is disclosed to be 5 to 8 μm. By controlling the depth of the halftone dot structure within the above range, light can achieve an appropriate effect at the halftone dot structure, avoiding the impact on the brightness performance due to the structure being too deep or too shallow, and helping to balance optical effects and manufacturing stability.

[0008] Furthermore, in another embodiment, each of the backlight surfaces is disclosed as a curved surface. This allows for a smoother turning effect during light reflection or guidance, thereby helping to improve overall light output brightness and enhance the stability of light emission.

[0009] Based on the same technical concept, this invention proposes a backlight module in one embodiment, comprising: a light guide plate as described in the preceding embodiments; and an LED strip, disposed corresponding to the light-incident side, to provide side-incident light to the light guide plate. Through the above configuration, light can be effectively guided into the interior of the light guide plate in a side-incident manner, and in conjunction with the structural design of the light guide plate, the light can be stably transmitted and effectively utilized.

[0010] In another embodiment, the backlight module further includes a reflector disposed on the bottom side of the light guide plate, thereby reflecting downward-scattering light back into the light guide plate to reduce light energy loss and improve overall light output efficiency.

[0011] To improve the light reflection efficiency of the reflective sheet, a further embodiment discloses that the reflective sheet has a metallic silver coating and a matte finish. This allows for more dispersed reflected light, thereby improving brightness uniformity and reducing localized brightness concentration.

[0012] In addition, in one embodiment, the backlight module also includes a diffuser sheet stacked on the top side of the light guide plate to diffuse the emitted light, which can further balance the brightness distribution and make the light output more uniform.

[0013] Furthermore, to improve the overall light output brightness of the backlight module and enhance the effective utilization of light, another embodiment discloses that the backlight module also includes a brightness enhancement structure stacked on the top side of the diffuser sheet. Accordingly, light can be concentrated in the effective light output direction, thereby improving the light output brightness.

[0014] In another embodiment, the brightness enhancement structure includes a first prism sheet and a second prism sheet stacked vertically, with the prism directions of the first prism sheet and the second prism sheet intersecting each other at an angle of approximately 90 degrees. This intersecting prism structure guides light from different directions, thereby helping to improve the overall brightness concentration.

[0015] To enhance the rigidity and stability of the brightness enhancement structure, in another embodiment, the brightness enhancement structure includes an optically transparent adhesive layer disposed between the first prism sheet and the second prism sheet, so that the first prism sheet and the second prism sheet are bonded together. This effectively prevents the optical effect from being affected by component displacement.

[0016] In summary, the light guide plate and its backlight module of the present invention, through a dotted structure with a special structure and angle design, enable light to be effectively guided and adjusted within the light guide plate, exhibiting high brightness upon emission, thereby effectively improving light utilization efficiency. Based on this light guide plate, the backlight module disclosed in this invention further incorporates LED light strips, allowing the light source to enter the light guide plate from the side and be effectively guided by the dotted structure of the light guide plate, improving the overall light output brightness of the module during application and contributing to improving the light output quality of electronic products such as display devices using backlight modules. Furthermore, the present invention also proposes many additional technical features, the detailed technical features and corresponding effects of which are described in the preceding paragraphs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a light guide plate structure according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic cross-sectional view of a dotted structure according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the dot structure according to one embodiment of the present invention.

[0020] Figure 4 This is a cross-sectional schematic diagram of a backlight module structure according to an embodiment of the present invention. Detailed Implementation

[0021] As mentioned earlier, existing light guide plates still have room for improvement in terms of light output brightness in practical applications. Based on relevant technical background and practical experience, the applicant has re-examined the transmission and emission behavior of light within the light guide plate, and used a dotted structure as the starting point for the overall design. By adjusting its geometry and configuration, the light can be more effectively controlled during the guiding process, thereby improving the light output brightness. The following is a detailed description of the technical means of a light guide plate and its backlight module proposed in this invention, using text and accompanying drawings. The structural dimensions, proportions, sizes, shapes, or application states shown in the figures are merely illustrative and used to illustrate the technical features of this invention, and do not represent actual structural designs; this is hereby clarified.

[0022] Please refer to the following first. Figure 1This is a schematic diagram of a light guide plate structure according to an embodiment of the present invention. The present invention discloses a light guide plate 1 and its backlight module. The technical features of the light guide plate 1 will be described first. The light guide plate 1 has a light-incident side surface 10, an upper surface 11, and a lower surface 12. The upper surface 11 and the lower surface 12 are arranged opposite to each other and are respectively adjacent to the light-incident surface 10. The light guide plate 1 is characterized in that its upper surface 11 or lower surface 12 has a plurality of dot structures 13. Each dot structure 13 is a concave structure and has a light-facing surface 131 and a backlight surface 132. In this embodiment, these dot structures 13 are located on the lower surface 12 as an example. For further explanation of the angular characteristics of each dot structure 13, please refer to [the relevant documentation / reference needed]. Figure 2 This is a schematic cross-sectional view of the dot structure according to an embodiment of the present invention. In the cross-section AA where each dot structure 13 is perpendicular to both the upper surface 11 and the lower surface 12, and also perpendicular to the light-incident side surface 10, the angle θ1 between the first line segment 1311 formed by the light-facing surface 131 and the vertical line V is 50-60 degrees, and the angle θ2 between the second line segment 1321 formed by the backlight surface 132 and the vertical line V is 30-50 degrees. The angle θ3 between the reference plane S, which is perpendicularly extended from the line connecting any two points on the edge of the backlight surface 132, and the backlight surface 132 is 10-30 degrees. For ease of understanding, please refer to the following: Figure 3 This is a schematic diagram of the dot structure according to an embodiment of the present invention, showing the reference plane S, the backlight plane 132, and the included angle θ3. For illustrative purposes, [the diagram is omitted here]. Figure 3 The dot structure 13 is drawn with solid lines, but in this embodiment, the dot structure 13 is actually located on the lower surface 12 of the light guide plate 1 and cannot be directly observed. Please refer to the accompanying documentation. Figure 1 Refer to its actual configuration status.

[0023] Experiments show that the design of each angle of the dot structure 13 on the light guide plate 1 has a significant impact on the output brightness. When the angle θ1 between the first line segment 1311 formed by the light-facing surface 131 in the cross section AA and the vertical line V is controlled between 50 and 60 degrees, the light rays, after being guided by the dot structure 13, present a more positive emission angle and increase the brightness by 12 to 15%. Compared with the cases where the angle is too small or too large, the brightness increase is significantly improved, indicating that this range is the optimal range for light output efficiency.

[0024] On the other hand, the angle θ2 between the second line segment 1321 formed by the backlight surface 132 at section AA and the vertical line V also plays a crucial role in brightness stability. Experimental results show that when the angle θ2 is between 30 and 50 degrees, the dot structure 13 has the least impact on brightness attenuation, causing almost no light loss; if the angle is too small or too large, it may result in a brightness decrease of about 1% to 3%. Therefore, designing the angle θ2 within the range of 30 to 50 degrees can effectively maintain overall light output stability.

[0025] Furthermore, the side angle of the backlight surface 132, i.e., the angle θ3 between the reference plane S and the backlight surface 132, also affects the increase in light output brightness. Tests show that when the angle θ3 is controlled between 10 and 30 degrees, the light guide plate 1 can achieve a stable and relatively high brightness increase, reaching approximately 15-17%. As the side angle gradually increases, the brightness increase gradually decreases. An excessively large side angle reduces the effective area of ​​the light-facing surface 131, thereby reducing the brightness increase efficiency. By comprehensively designing the above three angle parameters, the dot structure 13 can achieve the best guiding effect in the light guide plate 1, improving the light output brightness and maintaining a stable light distribution.

[0026] Accordingly, this invention provides a dotted structure 13 with a specific geometric angle configuration on the light guide plate 1, and coordinates the design of the angles of the light-facing surface 131, the backlight surface 132, and the side angles of the backlight surface 132 (i.e., the aforementioned included angles θ1, θ2, and θ3). This allows the light incident on the light guide plate 1 to be effectively guided and controlled during transmission and emission. Furthermore, by integrating and controlling the multi-angle geometric relationships, this invention enables the light to simultaneously improve the output brightness and maintain brightness stability at the dotted structure 13, thereby effectively improving the light extraction efficiency of the light guide plate 1.

[0027] Regarding the depth of the dot structure 13, the present invention also proposes suitable examples. In one embodiment, the depth of each dot structure 13 can be 5 to 8 μm, for example, 5.5, 6.2, or 7.6 μm. By controlling the depth of the dot structure 13 within the above range, after light enters, a suitable reflection and guiding path can be formed under the geometric combination of the light-facing surface 131 and the backlight surface 132, thereby enabling the light to be effectively emitted in the light-emitting direction. At the same time, it avoids insufficient guiding effect due to the structure being too shallow, or light retention, scattering, or reduced light emission efficiency due to the structure being too deep.

[0028] In the geometric definition of the dot structure 13 described above, the angle θ3 between the reference plane S, which is perpendicularly extended from the line connecting any two points on the edge of the backlight surface 132, and the backlight surface 132 is used to describe the tilt state of the backlight surface 132 relative to the reference plane S in a local area. The backlight surface 132 can be composed of multiple interconnected tilted surfaces, or it can be a smooth curved surface that changes continuously along a specific direction. As long as the aforementioned angle range can be formed at any local position, it meets the design conditions of the present invention. In this embodiment, the backlight surface 132 is taken as an example with an arc surface structure, so that the tilt angle of the backlight surface 132 changes continuously along its contour direction. This allows the light to turn more smoothly during the guidance and reflection process, which helps to maintain the stability of the emitted light brightness and improve the overall light distribution. The reference plane is usually perpendicular to the "upper or lower surface of the light guide plate" or perpendicular to the "light incident side". In this embodiment, "vertical extension" means "extending perpendicular to the main plane (upper / lower surface) of the light guide plate".

[0029] Please continue to refer to the accompanying materials. Figure 4 This is a cross-sectional schematic diagram of a backlight module structure according to an embodiment of the present invention. The structure of the backlight module 2 having the light guide plate 1 will be further described below. Specifically, the backlight module 2 includes the light guide plate 1 and LED strips 20 as described above. The LED strips 20 are disposed on the light-incident side 10 of the light guide plate 1 to provide side-incident light to the light guide plate 1. Through this side-incident light configuration, the light can be uniformly and effectively guided into the interior of the light guide plate 1. Combined with the geometric design of the dot structure 13, the light obtains a more stable transmission and emission direction during the guiding process, thereby improving the overall light output brightness and light utilization efficiency.

[0030] Furthermore, to further improve the light energy utilization efficiency of the backlight module 2, other optical components can be added to the backlight module 2. For example, the backlight module 2 may also include a reflective sheet 21, which is disposed on the bottom side of the light guide plate 1. Through the reflective sheet 21, the downward-scattered light can be reflected back into the interior of the light guide plate 1, reducing light energy loss and guiding the light back to the light output direction, thereby improving the overall light output efficiency.

[0031] Furthermore, this embodiment also discloses that, to improve the light reflection utilization effect of the reflective sheet 21, the reflective sheet 21 can be made of a sheet material with a metal coating and a matte finish. The metal coating increases reflectivity, thereby improving the upward light guiding efficiency; while the matte finish allows for a more uniform distribution of reflected light, avoiding localized brightness concentration, thus improving the brightness uniformity and overall light efficiency of the backlight module 2. The metal coating can be made of silver, which combines high reflectivity with manufacturing stability.

[0032] In addition, the backlight module 2 may further include a diffuser 22, which is stacked on the top side of the light guide plate 1 to diffuse the emitted light, making the light distribution more uniform, reducing brightness concentration and dark spot phenomena, thereby improving the uniformity of light output and the overall visual quality.

[0033] To further enhance the light output brightness of the backlight module 2, the backlight module 2 may also include a brightness enhancement structure 23, which is stacked on the top side of the diffuser 22. Through the brightness enhancement structure 23, the light transmitted by the light guide plate 1 and the diffuser 22 can be concentrated in the effective light output direction, enhancing the light utilization efficiency and thus improving the light output brightness performance, while maintaining uniform light distribution and improving the overall visual effect.

[0034] Furthermore, one structural configuration of the brightness enhancement structure 23 may include a first prism sheet 231 and a second prism sheet 232 stacked vertically, with the prism directions of the first prism sheet 231 and the second prism sheet 232 intersecting each other at an angle of approximately 90 degrees. This intersecting prism structure allows light rays from different directions to be guided and refracted, concentrating the light in the effective light-emitting direction, thereby improving the overall brightness concentration while maintaining uniform brightness distribution and improving the visual consistency and luminous efficacy of the light-emitting surface.

[0035] In addition, to enhance the structural rigidity and stability of the brightness enhancement structure 23 and prevent the light guiding effect and overall brightness performance from being affected by prism displacement, warping, or vibration, the brightness enhancement structure 23 may also include an optically transparent adhesive layer 233, disposed between the first prism sheet 231 and the second prism sheet 232, so that the first prism sheet 231 and the second prism sheet 232 are bonded together. Through the bonding of the optically transparent adhesive layer 233, the precise alignment between the prism sheets can be maintained, ensuring that light can still obtain a stable and effective guiding effect when passing through the brightness enhancement structure 23, while improving the overall durability and operational reliability of the structure.

[0036] In summary, the light guide plate and its backlight module structure of the present invention, through the dot structure with a specific geometric angle configuration on the light guide plate, can effectively control the transmission and emission direction of light within the light guide plate, enabling the light to simultaneously improve brightness and maintain brightness stability. Furthermore, the depth of the dot structure is controlled within the range of 5–8 μm, ensuring that the light forms an appropriate reflection path during the guiding process, avoiding insufficient guiding effect due to excessive shallowness or light stagnation and efficiency reduction due to excessive depth. The curved backlight surface allows the light to smoothly turn along the contour direction, further stabilizing the light distribution. The side-incident lighting arrangement of the light guide plate and LED light strips enables the backlight module constructed accordingly to obtain uniform and effective light input, resulting in good brightness performance and uniform light distribution. The backlight module can also be equipped with a reflective sheet to reflect downward-scattered light back into the light guide plate, enhancing light utilization efficiency. In addition, the high reflectivity and matte finish of the reflective sheet can reduce light energy loss and improve light distribution uniformity. When the backlight module includes a diffuser, it can further homogenize the light, reducing brightness concentration and dark spots. The brightness enhancement structure can improve light concentration and guide the light in an effective output direction. The brightness enhancement structure can be further configured to include a first prism and a second prism, with their prism directions intersecting at an angle of approximately 90 degrees to concentrate the light and maintain uniform brightness. In addition, to further improve structural stability and rigidity, the brightness enhancement structure may include an optically transparent adhesive layer to bond the first and second prisms together, preventing displacement or warping from affecting the light guiding effect, thereby ensuring the overall backlight module's output brightness, light distribution uniformity, and structural reliability.

[0037] [Explanation of Labels in the Attached Image]

[0038] 1. Light guide plate

[0039] 10. Side view of incoming light

[0040] 11. Top surface

[0041] 12 Lower surface

[0042] 13. Network Structure

[0043] 131 Sunlit side

[0044] 1311 First line segment

[0045] 132 Backlight

[0046] 1321 Second line segment

[0047] 2 Backlight Module

[0048] 20 LED light strips

[0049] 21 Reflective sheet

[0050] 22 diffusion sheet

[0051] 23 Brightness enhancement structure

[0052] 231 First Prism Slide

[0053] 232 Second Prism Slide

[0054] 233 Optically Transparent Adhesive Layer

[0055] V vertical line

[0056] S reference plane

[0057] θ1 The angle between the first line segment and the perpendicular line

[0058] θ2 The angle between the second line segment and the perpendicular line

[0059] θ3 is the angle between the reference plane and the backlight plane.

Claims

1. A light guide plate having a light-incident side, an upper surface, and a lower surface, wherein the upper surface and the lower surface are arranged opposite to each other and are respectively adjacent to the light-incident side, characterized in that: The upper or lower surface of the light guide plate has multiple dot structures, each dot structure being a recessed structure with a light-facing surface and a backlight surface. In a cross-section where each dot structure is perpendicular to both the upper and lower surfaces and to the light-incident side, the angle between the first line segment formed by the light-facing surface and the vertical line is 50 to 60 degrees, and the angle between the second line segment formed by the backlight surface and the vertical line is 30 to 50 degrees. Furthermore, the angle between the reference plane perpendicularly extended from the line connecting any two points on the edge of the backlight surface and the backlight surface is 10 to 30 degrees.

2. The light guide plate according to claim 1, wherein, The depth of each of the described dot structures is 5–8 μm.

3. The light guide plate according to claim 1, wherein, Each of the backlight surfaces is a curved surface.

4. A backlight module, comprising: Light guide plate as described in any one of claims 1 to 3; and LED light strips are arranged corresponding to the light-incident side to provide side-incident light to the light guide plate.

5. The backlight module according to claim 4 further includes a reflective sheet disposed on the bottom side of the light guide plate.

6. The backlight module according to claim 5, wherein, The reflector has a metallic silver coating and a matte finish.

7. The backlight module according to claim 4 further includes a diffuser sheet stacked on the top side of the light guide plate.

8. The backlight module according to claim 7 further includes a brightness enhancement structure stacked on the top side of the diffuser sheet.

9. The backlight module according to claim 8, wherein, The brightness enhancement structure includes a first prism sheet and a second prism sheet stacked vertically, wherein the prism directions of the first prism sheet and the second prism sheet intersect each other at an angle of approximately 90 degrees.

10. The backlight module according to claim 9, wherein, The brightness enhancement structure includes an optically transparent adhesive layer disposed between the first prism sheet and the second prism sheet to bond the first prism sheet and the second prism sheet together.

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