A front light guide plate based on UV coating composite dot structure

Abstract

The utility model discloses a front light guide plate based on UV coating composite dot structure is provided with light guide plate base material, hot pressure dot layer, UV solidification optical coating and OCA optical adhesive layer from bottom to top in proper order. The multiple micron level concave dots formed on one surface of the light guide plate base material through hot pressure transfer printing process, and the cross section is in inverted crater shape. These dots are the initial control structure of light emission. The coating completely fills and copies the shape of each hot pressure concave dot, thereby forming the complementary convex UV dot on the basis of the hot pressure concave dot. The hot pressure concave dot and the UV convex dot jointly constitute the composite dot structure. The structure can perfectly adapt to full lamination process, effectively solve the problem of brightness decline caused by full lamination, and eliminate the defects such as white fogging, easy to enter foreign matter and poor reliability of frame pasting scheme.

Description

Technical Field

[0001] This utility model relates to the field of light guide plate technology, specifically a front light guide plate based on a UV-coated composite dot structure. Background Technology

[0002] Reflective liquid crystal displays (RLCDs), utilizing ambient light for display, offer significant advantages such as extremely low power consumption, comfortable and natural visual experience, and eye protection, making them widely used in e-book readers, retail terminals, industrial instruments, and IoT electronic tags. Current mainstream RLCD front light modules employ a hot-pressed dot-matrix light guide plate, attached to the outer perimeter of the display cover plate via double-sided adhesive, creating a hollow area between the dot surface of the light guide plate and the cover plate. This solution has inherent drawbacks: the dots are prone to strong scattering in the air, producing a "white fog" phenomenon that reduces image clarity; the hollow area is susceptible to dust and moisture intrusion, and the stress exerted during pressing directly on the light guide plate can easily cause it to crack or damage the dots; the double-sided adhesive fixing also carries the risk of assembly misalignment and aging displacement. Furthermore, the refractive index mismatch between the traditional hot-pressed dot-matrix light guide plate and the adhesive results in significant light energy loss and a sharp drop in brightness, failing to meet usage requirements. Utility Model Content

[0003] In order to overcome the shortcomings of existing technical solutions, this utility model provides a front light guide plate based on a UV-coated composite dot structure, which can effectively solve the problems mentioned in the background technology.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A front light guide plate based on a UV-coated composite dot structure comprises, from bottom to top, a light guide plate substrate, a hot-pressed dot layer, a UV-cured optical coating, and an OCA optical adhesive layer.

[0006] The hot-pressed dot layer is formed on the upper surface of the light guide plate substrate. The hot-pressed dot layer is composed of multiple micron-sized concave dots, and the cross-section of the concave dots is shaped like an inverted volcano.

[0007] The UV-cured optical coating completely covers and adheres to the upper surface of the hot-pressed dot layer, and the UV-cured optical coating completely fills the internal space of the concave dots and replicates the shape of the concave dots, so that the lower surface of the UV-cured optical coating forms convex dots that are complementary to the concave dots. The concave dots and convex dots together constitute a composite dot structure. The OCA optical adhesive layer is coated or adhered to the flat upper surface of the UV-cured optical coating for full adhesion with the front cover of the display device.

[0008] As a further description of the above technical solution, the material of the light guide plate substrate is a high light transmittance polymer, which is selected from any one of polycarbonate, polymethyl methacrylate or cyclic olefin copolymer.

[0009] As a further description of the above technical solution, the depth of the concave dots in the hot-pressed dot layer is 8μm-15μm.

[0010] As a further description of the above technical solution, the thickness of the UV-curable optical coating is 50μm±5μm, the upper surface of the UV-curable optical coating is a flat surface, and the refractive index of the UV-curable optical coating is 1.50-1.60.

[0011] As a further description of the above technical solution, the material of the UV-curable optical coating is a light-guiding UV-curable ink, and the light-guiding UV-curable ink forms the smooth upper surface of the UV-curable optical coating after being irradiated and cured by UV light of a specific wavelength.

[0012] As a further description of the above technical solution, the thickness of the OCA optical adhesive layer is 50μm-200μm.

[0013] As a further description of the above technical solution, the cross-sectional profile of the convex dots is completely complementary to the cross-sectional profile of the concave dots.

[0014] As a further description of the above technical solution, the side of the OCA optical adhesive layer away from the UV-cured optical coating is used to bond with the front cover plate, which is a glass cover plate or a transparent polymer cover plate, and the OCA optical adhesive layer and the front cover plate are bonded together to form an integrated structure without bubbles or gaps.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] The front light guide plate based on a UV-coated composite dot structure of this utility model has at least one of the following beneficial effects during use:

[0017] By utilizing the refractive index difference between the light guide plate substrate and the UV coating, the composite dot structure achieves multiple refractions and coupling of light, significantly improving light extraction efficiency and solving the brightness attenuation problem caused by full lamination. The full lamination structure eliminates air gaps, fundamentally preventing dot scattering in the air, resulting in greatly improved image clarity and contrast. The UV coating completely encapsulates and cures the fragile hot-pressed dots, forming a robust protective layer that effectively prevents damage from pressure or impact. The full lamination structure eliminates hollow areas, preventing dust and moisture intrusion and improving product durability in harsh environments. Overall yield is high, and costs are controllable. OCA adhesive full lamination provides stronger bonding strength and stability than double-sided tape, eliminating the risk of misalignment or displacement. Hot-pressed dots can be independently optimized, and then optical gain and physical protection are achieved through the UV coating, realizing the "decoupling" of design and performance. The UV coating surface naturally forms extremely high flatness, providing an ideal interface for subsequent full lamination processes. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the composite dot structure of a front light guide plate based on a UV-coated composite dot structure according to this utility model.

[0019] Figure 2 This utility model Figure 1 Schematic diagram of part A in the middle.

[0020] Numbering on the map:

[0021] 1. Light guide plate substrate; 2. UV-cured optical coating; 3. OCA optical adhesive layer; 4. Convex dots; 5. Concave dots. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] like Figure 1-2 As shown, this utility model provides a front light guide plate based on a UV-coated composite dot structure, characterized in that a light guide plate substrate 1, a hot-pressed dot layer, a UV-cured optical coating 2, and an OCA optical adhesive layer 3 are stacked sequentially from bottom to top.

[0024] The hot-pressed dot layer is formed on the upper surface of the light guide plate substrate 1. The hot-pressed dot layer is composed of multiple micron-sized concave dots 5, and the cross-section of the concave dots 5 is shaped like an inverted volcano.

[0025] The UV-cured optical coating completely covers and encapsulates the hot-pressed dot layer, forming a robust protective layer that can withstand compressive stress (such as when a user touches the cover plate), avoiding the problem of "dots breaking under direct force" in traditional frame-mounted stickers.

[0026] The UV-curable optical coating 2 completely covers and adheres to the upper surface of the hot-pressed dot layer, and the UV-curable optical coating 2 completely fills the internal space of the concave dot 5 and replicates the shape of the concave dot 5, so that the lower surface of the UV-curable optical coating 2 forms a convex dot 4 that is complementary to the concave dot 5. The concave dot 5 and the convex dot 4 together constitute a composite dot structure. The OCA optical adhesive layer 3 is coated or adhered to the flat upper surface of the UV-curable optical coating 2 for full adhesion with the front cover of the display device.

[0027] The fabrication process of the front light guide plate in this embodiment is as follows: using a steel plate mold with a pre-etched target dot pattern, a precise inverted volcano-shaped concave dot pattern 5 is formed on the clean light guide plate substrate 1 surface through a hot pressing transfer process.

[0028] Perform plasma cleaning or solvent cleaning on the surface of the light guide plate that has completed hot-pressing dots to ensure that the surface is free of contaminants such as grease and dust.

[0029] A layer of light-guiding UV ink with a specific formula is uniformly coated on the dot surface of the light guide plate using slit coating or scraping methods. The wet film thickness is controlled by precision coating equipment so that the dry film thickness of the cured UV coating is 0.05 mm.

[0030] Under nitrogen protection, the coating is irradiated with a UV-LED lamp of a specific wavelength, causing it to cure rapidly. After curing, the UV coating perfectly replicates the hot-pressed dot pattern below, forming stable UV raised dots.

[0031] Using OCA optical adhesive, the UV-coated surface of the light guide plate, after the above treatment, is vacuum-bonded to the front cover plate of the display, forming a seamless, bubble-free integrated structure. This fully bonded structure eliminates air gaps, fundamentally preventing dot scattering in the air, and significantly improving image clarity and contrast.

[0032] Furthermore, the material of the light guide plate substrate 1 is a high light transmittance polymer, which is selected from any one of polycarbonate, polymethyl methacrylate or cyclic olefin copolymer.

[0033] A 0.7mm thick PC sheet is selected as the light guide plate substrate 1. As the core carrier for light propagation, the light guide plate substrate 1 uses high-transmittance polymers such as polycarbonate (PC) and polymethyl methacrylate (PMMA) (transmittance ≥90%) to ensure that light incident from the side of the substrate (from the LED light source of the front light module) can propagate internally with low loss, avoiding brightness attenuation due to light absorption by the material itself.

[0034] By utilizing the refractive index difference between the light guide plate substrate 1 and the UV coating, the composite dot structure enables multiple refractions and coupling of light, significantly improving light extraction efficiency and solving the brightness attenuation problem caused by full lamination.

[0035] Furthermore, the depth of the concave dots 5 in the hot-pressed dot layer is 8μm-15μm.

[0036] Using a steel plate mold with a cell depth of 11μm, hot pressing transfer is performed at 110℃ and 0.4MPa pressure to form a periodic array of inverted volcano-shaped dots. A UV coating completely covers and cures the fragile hot-pressed dots, forming a robust protective layer that effectively prevents damage to the dots under pressure or impact. The design (density, size, and shape) of the hot-pressed dots can be optimized independently, and then optical gain and physical protection are achieved through UV coating, thus decoupling design from performance.

[0037] Furthermore, the thickness of the UV-curable optical coating 2 is 50μm±5μm, the upper surface of the UV-curable optical coating 2 is a flat surface, and the refractive index of the UV-curable optical coating 2 is 1.50-1.60.

[0038] After the UV coating cures, it naturally forms a smooth upper surface, requiring no additional sanding or treatment, and can be directly bonded to the OCA adhesive layer.

[0039] Furthermore, the material of the UV-curable optical coating 2 is a light-guiding UV-curable ink. After being irradiated with UV light of a specific wavelength, the light-guiding UV-curable ink forms the smooth upper surface of the UV-curable optical coating 2.

[0040] A light-guiding UV ink with a refractive index of 1.56 was applied using a slot coater at a speed of 2 m / min, with the wet film thickness controlled at 55 μm. The coated light guide plate was then placed in a nitrogen-protected UV curing oven at a wavelength of 365 nm and a curing temperature of 800 mJ / cm². 2 Cured under high energy. A precise inverted crater-shaped concave dot pattern 5 is formed on the clean surface of the light guide plate substrate 1. The UV coating surface naturally forms an extremely high degree of flatness, providing an ideal interface for subsequent full lamination processes.

[0041] Furthermore, the thickness of the OCA optical adhesive layer 3 is 50μm-200μm.

[0042] The adhesive layer thickness is controlled at 50μm-200μm, with a light transmittance of ≥90% and a haze of ≤1%, ensuring that there is no additional scattering or absorption of light when it passes through. At the same time, the adhesive layer is completely bonded to the flat upper surface of the UV coating, eliminating the hollow area of ​​the traditional "frame bonding" and avoiding light scattering at the "dot-air" interface.

[0043] Furthermore, the cross-sectional profile of the convex dot 4 is completely complementary to the cross-sectional profile of the concave dot 5.

[0044] Furthermore, the side of the OCA optical adhesive layer 3 away from the UV-cured optical coating 2 is used to bond with the front cover plate, which is a glass cover plate or a transparent polymer cover plate. After the OCA optical adhesive layer 3 is bonded to the front cover plate, it forms an integrated structure without bubbles or gaps.

[0045] Using 100μm thick transparent OCA optical adhesive, the light guide plate and glass cover are fully bonded in a vacuum laminator. This full-bonding structure eliminates hollow areas, preventing dust and moisture intrusion and improving the product's durability in harsh environments. The OCA adhesive full-bonding provides bonding strength and stability far exceeding that of double-sided tape, eliminating the risk of misalignment or displacement.

[0046] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A front light guide plate based on a UV-coated composite dot structure, characterized in that: The light guide plate substrate, the hot-pressed dot layer, the UV-cured optical coating, and the OCA optical adhesive layer are stacked sequentially from bottom to top. The hot-pressed dot layer is formed on the upper surface of the light guide plate substrate. The hot-pressed dot layer is composed of multiple micron-sized concave dots, and the cross-section of the concave dots is shaped like an inverted volcano. The UV-cured optical coating completely covers and adheres to the upper surface of the hot-pressed dot layer, and the UV-cured optical coating completely fills the internal space of the concave dots and replicates the shape of the concave dots, so that the lower surface of the UV-cured optical coating forms convex dots that are complementary to the concave dots. The concave dots and convex dots together constitute a composite dot structure. The OCA optical adhesive layer is coated or adhered to the flat upper surface of the UV-cured optical coating for full adhesion with the front cover of the display device.

2. The front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The light guide plate substrate is made of a high-transmittance polymer, which is selected from any one of polycarbonate, polymethyl methacrylate or cyclic olefin copolymer.

3. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The depth of the concave dots in the hot-pressed dot layer is 8μm-15μm.

4. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The thickness of the UV-curable optical coating is 50μm±5μm, the upper surface of the UV-curable optical coating is flat, and the refractive index of the UV-curable optical coating is 1.50-1.

60.

5. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The UV-curable optical coating is made of light-guiding UV-curable ink. After being cured by UV light of a specific wavelength, the light-guiding UV-curable ink forms the smooth upper surface of the UV-curable optical coating.

6. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The thickness of the OCA optical adhesive layer is 50μm-200μm.

7. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The cross-sectional profile of the convex dots is completely complementary to that of the concave dots.

8. A front light guide plate based on a UV-coated composite dot structure according to claim 1, characterized in that: The side of the OCA optical adhesive layer away from the UV-cured optical coating is used to bond with the front cover plate, which is a glass cover plate or a transparent polymer cover plate. After the OCA optical adhesive layer is bonded to the front cover plate, it forms an integrated structure without bubbles or gaps.

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