A liquid crystal display unit with zero visual seam

Abstract

The application discloses a kind of zero visual seam's liquid crystal display unit, it is related to display technical field.The display unit includes backlight module, liquid crystal panel assembly and optical compensation composite cover plate.Wherein, the edge of backlight module is equipped with the chamfer support surface that is inwards shrinkage, the non-display area of liquid crystal panel assembly is bent or adhered along the chamfer support surface, so that the physical height of non-display area is lower than the plane where effective display area is located.Optical compensation composite cover plate is adhered to the surface of liquid crystal panel assembly and extends to cover above non-display area, and the cover plate sequentially includes light remodeling layer, waveguide light uniform layer and wide-angle scattering layer from bottom to top.The application is cooperated by mechanical structure and micro-nano optics, realizes the visual screening of physical seam under the premise of not increasing electronic control complexity, solves the problems of large assembly thickness, black seam ghost and edge image distortion in traditional seam elimination scheme.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a liquid crystal display unit with zero visual seam. Background Technology

[0002] LCD video walls are widely used in command and control centers, security monitoring, broadcasting studios, and large-scale commercial exhibitions due to their high resolution, low power consumption, long lifespan, and relatively low cost. However, due to the limitations of the imaging principle of LCD panels, a sealing frame for encapsulating liquid crystal molecules and a non-display area for arranging gate driving circuits must be reserved around the perimeter. This inevitably results in physical bezels when multiple display units are spliced ​​together. Although advancements in manufacturing processes in recent years have reduced the bezel width from over 20mm to an astounding 0.88mm or even smaller, the crisscrossing black grids still create a strong sense of visual discontinuity in high-definition large-screen images, disrupting the overall integrity and immersive experience of the picture, and failing to meet the stringent requirements of "seamless full-screen" in the high-end display field. Therefore, how to eliminate this black border through physical or optical means has become a pressing technical challenge for the industry.

[0003] To address the aforementioned seam issue, existing technologies typically employ optical refraction principles to conceal the physical bezel. For instance, Chinese authorized invention patent CN101770732B (invention title: "Seamless Splicing Display Device") discloses a typical technical solution. This patent describes a structure that incorporates an optical magnifying plate (i.e., a lens assembly) at the seam. The viewing surface of this optical magnifying plate is curved or a Fresnel lens surface, and a reflective surface is provided between the seam and the optical magnifying plate. The basic principle is to utilize the refraction and reflection of the lens to magnify and deflect the image light from the edge of the LCD screen display area, covering the non-illuminated physical bezel. This allows the observer to not see the black seam at the splicing point within a certain viewing angle, achieving a visually seamless splicing.

[0004] However, the existing "refractive lens / magnifying plate" technical solution represented by CN101770732B has significant drawbacks:

[0005] First, there's the issue of thickness and volume: In order to achieve a sufficient light deflection angle to cover the physical bezel, such optical magnifying boards usually require a large curvature or prism structure, which leads to a significant increase in the thickness of the optical components on the surface of the display unit (often exceeding 10mm). This not only increases the weight and volume of the overall device, but also goes against the trend of modern display devices pursuing extreme thinness and lightness.

[0006] Secondly, viewing angle limitations and image distortion: Due to the limitations of the optical path design of a single lens or prism, its "seamless" effect is usually highly directional, limited to a small viewing angle directly in front of the screen; when the observer is viewing from a large angle to the side, the light cannot effectively cover the black edges, causing the black seams to reappear (i.e., "ghosting" or "faulting"); at the same time, after the edge image is greatly refracted and magnified, it is often accompanied by severe geometric distortion (stretching deformation) and brightness attenuation, resulting in a significant difference in the display effect between the splicing area and the central area, which seriously affects the overall consistency of the picture. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] To address the problems of large component thickness, ghosting when viewed from the side, and severe edge image distortion inherent in existing technologies that use large refractive prisms to eliminate LCD seams, this invention provides a zero-visual-seam LCD display unit. This display unit, through the synergistic design of a chamfered backlight structure and a composite micro-nano optical cover plate, achieves visual masking of the physical seam without increasing the complexity of electronic control, while also featuring a thin and light structure, a wide viewing angle, and a natural transition.

[0009] (II) Technical Solution

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] This invention provides a seamless liquid crystal display unit, mainly comprising a backlight module, a liquid crystal panel assembly, and an optical compensation composite cover plate. The backlight module provides the display light source, and its edge structure is specially designed with inwardly tapered chamfered support surfaces. The liquid crystal panel assembly is disposed on the light-emitting side of the backlight module, including a central effective display area and a surrounding non-display area (i.e., a physical black border). To accommodate the structure of the backlight module, the non-display area of ​​the liquid crystal panel assembly is bent or adhered along the chamfered support surface, making its physical height significantly lower than the plane of the effective display area, thus reserving space for light path guidance. The optical compensation composite cover plate is adhered to the surface of the liquid crystal panel assembly, covering the effective display area and extending above the non-display area. The cover plate contains a light guide structure configured to guide light emitted from the edge of the effective display area to be emitted directly above the non-display area, thereby visually obscuring the non-display area.

[0012] Furthermore, the optical compensation composite cover plate adopts a multi-layer composite structure, which consists of a light reshaping layer, a waveguide homogenizing layer, and a wide-angle scattering layer stacked from bottom to top.

[0013] Light reshaping layer: Adhered to the surface of the liquid crystal panel assembly, it contains micro-nano optical structures. Its function is to change the propagation direction of incident light, transforming the originally vertically emitted light into obliquely transmitted light.

[0014] Waveguide homogenizing layer: Located above the light reshaping layer, it is made of a high-refractive-index transparent medium and is used to receive light that has been repositioned and to transmit it laterally to the non-display area, so that the light can cross the physical black border.

[0015] Wide-angle scattering layer: Located above the waveguide uniform light layer, it serves as the final light-emitting surface of the display unit and is used to scatter the transmitted light to improve the viewing angle.

[0016] In a specific implementation, the micro-nano optical structure in the light reshaping layer is designed as an array of asymmetric microprism units. These microprism units are not distributed across the entire screen, but only above the edge source pixel area corresponding to a predetermined width of the effective display area. The tilt angle of the microprism units is specifically configured to refract vertically emitted light from the edge source pixel area into guided light that is tilted towards the non-display area.

[0017] To ensure a natural transition between images and avoid obvious dividing lines, the asymmetric microprism units are distributed in a gradient pattern on the light reshaping layer. Specifically, on the side farther from the non-display area (i.e., closer to the screen center), the distribution density of microprism units is lower or their size is smaller, resulting in a weaker deflection effect on light; while on the side closer to the non-display area (i.e., closer to the screen edge), the distribution density of microprism units is higher or their size is larger, resulting in a stronger deflection and guidance effect on light.

[0018] To ensure efficient light transmission, the refractive index of the waveguide homogenizing layer is set to be greater than that of the light reshaping layer and the external air, thereby satisfying the condition for total internal reflection transmission of light within the layer. This ensures that the light can be effectively constrained and "transported" to the area above the non-display area, rather than escaping midway.

[0019] To address the viewing angle issue, the wide-angle scattering layer employs a thin film with a microlens array structure on its surface or a thin film treated with anti-glare atomization. Its haze value is preferably controlled between 15% and 25%, which can convert the originally directional transmitted light into a light emission mode close to that of a Lambertian volume, allowing the illuminated seam area to be seen even when viewed from the side.

[0020] Furthermore, in terms of mechanical structure, the chamfered support surface of the backlight module is preferably tilted at an angle of 30 to 60 degrees relative to the bottom surface. The overall thickness of the optical compensation composite cover is preferably controlled within 3 mm, and the material can be selected from polycarbonate (PC), polymethyl methacrylate (PMMA), or glass-based composite materials to maintain the overall thin and light characteristics of the display.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention achieves a truly seamless visual effect through the synergistic design of a chamfered backlight module and an optical compensation composite cover plate, while significantly reducing the overall thickness of the display unit. By employing a backlight module with a chamfered support surface, the non-display area of ​​the LCD panel is physically sunken or bent, providing valuable vertical structural space for optical compensation. This eliminates the need for the thick, high-curvature solid refractive prisms used in traditional technologies, requiring only a thinner micro-nano structure composite layer to guide and cover the light laterally. This not only completely eliminates the visual disjointedness caused by the black physical bezel when splicing large screens, but also maintains the slim and lightweight appearance pursued by modern display devices, avoiding the bulky problem caused by excessively thick optical components.

[0023] This invention significantly improves the viewing angle and display uniformity of the splicing edges, solving the problem of "seamless front, black seams on the sides" in traditional technologies. By utilizing a wide-angle scattering layer located on the top layer of the cover plate, it effectively converts the directional light transmitted through the waveguide into uniform diffuse (Lambertian) light emission, overcoming the defects of traditional lens solutions that are prone to black seam "ghosting" or brightness discontinuity at side viewing angles, ensuring that users can observe a continuous seamless image across a wide viewing angle. At the same time, the microprism units in the light reshaping layer adopt a gradient distribution design from the inside out, realizing a smooth transition of image light from the central area to the edge area, effectively avoiding image abrupt changes, stretching deformation, or obvious dividing lines caused by sharp light deflection, ensuring the geometric continuity and visual naturalness of the spliced ​​image.

[0024] Furthermore, this invention improves the light energy utilization rate in the edge region; through the high refractive index total internal reflection transmission mechanism of the waveguide uniform light layer, the loss of light during lateral transmission is constrained to the maximum extent. Compared with the long optical path absorption inside the traditional solid lens material, this solution can more efficiently "transfer" the light energy of the source pixel to the area above the black border; combined with the effective containment of the physical frame by the chamfered structure, the brightness of the edge display area is kept in good consistency with the center area of ​​the screen, thereby significantly improving the overall visual quality and immersive experience of the splicing display wall. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] Figure 1 This is a schematic cross-sectional view of the splicing structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the core optical path principle of the present invention.

[0028] Reference numerals: 100, Liquid crystal display unit; 10, Backlight module; 11, Back panel frame; 12, Chamfered support surface; 20, Liquid crystal panel assembly; 21, Effective display area; 210, Edge source pixel area; 22, Non-display area; 30, Optical compensation composite cover plate; 31, Light reshaping layer; 32, Waveguide homogenizing layer; 33, Wide-angle scattering layer; L1, Incident light; L2, Conducted light; L3, Outgoing scattered light. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] like Figure 1 As shown, the present invention provides a liquid crystal display unit 100 with zero visual seam. The unit mainly consists of a backlight module 10, a liquid crystal panel assembly 20, and an optical compensation composite cover plate 30.

[0032] First, regarding the mechanical structure, the backlight module 10 includes a bottom backplate frame 11 for supporting the light guide plate, optical film, and light source. Unlike traditional backlight modules with vertical bezels, in this embodiment, the backlight module 10 has an inwardly tapered chamfered support surface 12 at its edge. The angle of inclination of this chamfered support surface 12 relative to the bottom surface of the backlight module is... The preferred setting is 45 degrees (which can be adjusted between 30 and 60 degrees); the liquid crystal panel assembly 20 is attached to the light-emitting side of the backlight module 10, which includes an effective display area 21 located in the center and a non-display area 22 surrounding the periphery (i.e., a physical black border, including a sealing frame and a GateIC driving circuit).

[0033] To accommodate the chamfered design of the backlight module 10, the non-display area 22 of the LCD panel assembly 20 employs flexible connection technology (such as COF packaging) or possesses a certain degree of flexibility, allowing it to bend or adhere downwards along the chamfered support surface 12. The key function of this structural design is to ensure that the highest physical point of the non-display area 22 is significantly lower than the horizontal plane where the effective display area 21 is located, thereby forming a physical "step" that provides sufficient thickness space for the optical compensation composite cover plate 30 above, without visually increasing the overall thickness abruptly.

[0034] like Figure 2 As shown, the optical compensation composite cover plate 30 is the core component of this invention. Its overall thickness is controlled at around 2.5 mm, and the material is a high-transmittance polycarbonate (PC) or polymethyl methacrylate (PMMA) composite material. This cover plate covers the entire effective display area 21 and extends outwards to cover the non-display area 22 directly above it. When two display units 100 are spliced ​​together, the edges of adjacent cover plates 30 are in close contact, thereby physically concealing the internal seam.

[0035] To achieve the optical "transfer" effect, the optical compensation composite cover plate 30 is divided into three layers from bottom to top in the vertical direction:

[0036] 1. Light Reshaping Layer 31 (Bottom Layer):

[0037] This layer is bonded to the surface of the liquid crystal panel assembly 20. Above the edge source pixel area 210, which is approximately 5mm-8mm wide and corresponds to the edge of the effective display area 21, the light reshaping layer 31 is formed with an array of asymmetric microprism units through a UV transfer process.

[0038] The distribution of these microprism units is not uniform, but rather exhibits a gradient variation: on the side closer to the center of the screen, the microprisms are smaller and sparsely distributed, resulting in a smaller deflection angle for light; as they extend towards the edge, the size of the microprisms gradually increases and their arrangement becomes more compact, resulting in a gradually increasing deflection angle for light.

[0039] Its working principle is as follows: the vertically incident light L1 from the edge source pixel area 210 is refracted by the asymmetric microprism unit and transformed into a guided light L2 that propagates obliquely toward the non-display area 22.

[0040] 2. Waveguide homogenizing layer 32 (intermediate layer):

[0041] This layer is located above the light reshaping layer 31 and is composed of a high refractive index (e.g., high refractive index). It is composed of a transparent medium; the thickness of this layer is designed to be 1.5 mm to 2.0 mm. Because its refractive index is higher than that of the light reshaping layer 31 below (or the air gap between them), the tilted light L2 entering this layer can be transmitted laterally in the layer in a manner of near total internal reflection or high-efficiency refraction, thereby "transporting" light energy from the edge of the effective display area 21 across to the top of the non-display area 22.

[0042] 3. Wide-angle scattering layer 33 (top layer):

[0043] This layer is located above the waveguide homogenizing layer 32 and serves as the final light-emitting surface of the display unit. In this embodiment, the wide-angle scattering layer 33 is a thin film with a microlens array imprinted on its surface, and its haze value is set to 20%.

[0044] Its function is to receive the directional light transmitted from the waveguide homogenizing layer 32 and disperse it, converting it into scattered light L3 that radiates uniformly in all directions. This allows the observer to see the luminous image covering the non-display area 22 whether viewed from the front or the side, thereby eliminating the black slit ghosting at the side viewpoint and ensuring that the brightness at the splicing point is consistent with the center of the screen.

[0045]

Example 2

[0046] The main difference between this embodiment and Embodiment 1 lies in the way the optical compensation composite cover plate 30 is supported above the non-display area 22.

[0047] In Embodiment 1, the cover plate 30 has a cantilever beam structure above the non-display area 22. In Embodiment 2, in order to enhance the mechanical stability of the structure, especially in large-size splicing units, a transparent optical adhesive (OCA) or a low-refractive-index transparent resin filler layer (not shown) is filled between the non-display area 22 (i.e., the physical black edge) and the extension of the optical compensation composite cover plate 30.

[0048] This filler layer not only provides physical support to prevent the cover plate edges from collapsing, but its refractive index is also configured to be lower than that of the waveguide homogenizing layer 32 to maintain the light transmission conditions of the waveguide layer and prevent premature light leakage and absorption. This structure is more suitable for video wall applications where touch-sensitive stability is required.

[0049] In summary, this invention, through a unique chamfered backlight structure combined with a three-layer gradient micro-nano optical cover plate, successfully solves the problems of large thickness, narrow viewing angle, and severe distortion in traditional LCD splicing black border removal technology, and realizes a thin and light display unit with excellent visual effects and zero splicing seam.

[0050] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A liquid crystal display unit with zero visual seam, characterized in that, include: Backlight module (10) is used to provide a display light source; A liquid crystal panel assembly (20) is disposed on the light-emitting side of the backlight module (10), including an effective display area (21) located in the center and a non-display area (22) surrounding the effective display area (21); and An optical compensation composite cover plate (30) is attached to the surface of the liquid crystal panel assembly (20); The backlight module (10) has an inwardly tapered chamfered support surface (12) at its edge. The non-display area (22) of the liquid crystal panel assembly (20) is bent or attached along the chamfered support surface (12), so that the physical height of the non-display area (22) is lower than the plane where the effective display area (21) is located. The optical compensation composite cover plate (30) covers the effective display area (21) and extends to cover the non-display area (22). The optical compensation composite cover plate (30) is provided with a light guide structure, which is configured to guide the light emitted from the edge of the effective display area (21) to be emitted directly above the non-display area (22) so as to visually block the non-display area (22).

2. The zero-visual-seam liquid crystal display unit according to claim 1, characterized in that, The optical compensation composite cover plate (30) consists of the following layers stacked from bottom to top: A light reshaping layer (31) is attached to the surface of the liquid crystal panel assembly (20) and includes micro-nano optical structures for changing the propagation direction of incident light. The waveguide homogenizing layer (32), located above the light reshaping layer (31), is made of a high refractive index transparent medium and is used to laterally transmit the light that has been reshaped to the direction of the non-display area (22). The wide-angle scattering layer (33) is located above the waveguide uniform light layer (32) and serves as the light-emitting surface of the display unit, used to scatter the transmitted light.

3. A zero-visual-seam liquid crystal display unit according to claim 2, characterized in that, The micro-nano optical structure in the light reshaping layer (31) is an array of asymmetric microprism units; The asymmetric microprism units are distributed only above the edge source pixel area (210) corresponding to the preset width of the edge of the effective display area (21); The tilt angle of the asymmetric microprism unit is configured such that the vertical outgoing light rays (L1) from the edge source pixel area (210) are refracted into guided light rays (L2) tilted toward the non-display area (22).

4. A zero-visual-seam liquid crystal display unit according to claim 3, characterized in that, The distribution of the asymmetric microprism units on the light reshaping layer (31) exhibits a gradient variation characteristic: On the side away from the non-display area (22), the distribution density of microprism units is smaller or the size is smaller; On the side closer to the non-display area (22), the distribution density of microprism units is greater or their size is larger; This achieves a smooth transition of light rays from the center area to the edge area of ​​the image.

5. A zero-visual-seam liquid crystal display unit according to claim 2, characterized in that, The refractive index of the waveguide homogenizing layer (32) is greater than that of the light reshaping layer (31) and the external air, so as to meet the condition for total internal reflection transmission of light within the layer, enabling light to cross the physical boundary between the effective display area (21) and the non-display area (22).

6. A zero-visual-seam liquid crystal display unit according to claim 2, characterized in that, The wide-angle scattering layer (33) is a thin film with a microlens array structure on its surface or a thin film treated with anti-glare atomization, with a haze value ranging from 15% to 25%, used to convert directionally transmitted light into Lambertian light emission.

7. A zero-visual-seam liquid crystal display unit according to claim 1, characterized in that, The chamfered support surface (12) is inclined at an angle of 30 degrees to 60 degrees relative to the bottom surface of the backlight module (10); The optical compensation composite cover plate (30) forms a cantilever structure in the portion corresponding to the non-display area (22) or is supported on the non-display area (22) by filling with transparent adhesive material.

8. A zero-visual-seam liquid crystal display unit according to claim 1, characterized in that, The overall thickness of the optical compensation composite cover plate (30) is less than 3 mm, and its material is selected from one or more of polycarbonate (PC), polymethyl methacrylate (PMMA) or glass-based composite materials.

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