Backlight module with ink brushed on light incident side of light guide plate of explosion-proof lamp and preparation method of backlight module

Abstract

The invention discloses a backlight module with ink brushed on the light incident side of a light guide plate of an explosion-proof lamp and a preparation method of the backlight module. The backlight module comprises a light guide plate, and a lower white ink layer and an upper black ink layer are sequentially arranged on the surface of the light incident side of the light guide plate. The white ink layer is used for reflecting light, the black ink layer is used for absorbing light and sealing, and the white ink layer and the black ink layer form an integrated structure with the light guide plate, so that a physical gap between the light guide plate and the LED reflecting component in the traditional design is thoroughly eliminated, and zero-gap sealing is realized. The invention further provides a corresponding preparation method. The preparation method comprises the steps of pretreatment, precise spraying of the double-layer printing ink, UV curing and the like. According to the invention, the light leakage problem of the light incident side of the light guide plate is fundamentally solved, and the illumination uniformity and the lighting effect are obviously improved; the reliability and environmental adaptability of the structure are enhanced, and the service life is prolonged; and meanwhile, the production process is simplified, the production cost is reduced, and the LED lamp is particularly suitable for the field of explosion-proof lighting with strict requirements on sealing performance and lighting effect.

Description

Technical Field

[0001] This invention relates to the field of semiconductor display technology, specifically to a backlight module with ink brushed on the light-incident side of an explosion-proof light guide plate and its preparation method. Background Technology

[0002] In the design and manufacturing of explosion-proof lamp backlight modules, to solve the light leakage problem on the light-incident side of the light guide plate, traditional technology typically employs an NB structure combined with an LED reflective tape bonding and a U-fold process. This solution reduces light leakage and the risk of lamp explosion by bonding LED reflective tape to the light-incident side of the light guide plate and using a U-fold structure to compress the Z-axis gap between the light guide plate and the LED reflective component to approximately 0.07mm. However, this technical solution still has the following significant drawbacks: First, although the Z-axis gap is significantly reduced, the gap still objectively exists, causing some light to leak out from the gap between the light guide plate and the LED reflective tape, resulting in light leakage and affecting the uniformity of illumination and safety of the explosion-proof light. Second, the LED reflective tape and the light guide plate are physically bonded together, and over long-term use, the tape is prone to shifting due to aging, weakened adhesion, or environmental factors, leading to an increased gap, exacerbating the light leakage problem, and affecting structural reliability and service life. Furthermore, the U-fold structure requires high processing precision and assembly technology, which not only increases production difficulty and cost but also makes it difficult to completely guarantee gap consistency in mass production, resulting in poor process controllability.

[0003] In summary, existing explosion-proof lamp backlight modules still suffer from problems in their light-leakage prevention design on the light guide plate's light-incident side, including reliance on external bonding components, insufficient long-term reliability, complex manufacturing processes, and difficulty in completely eliminating gaps. These issues hinder further improvements in the light efficiency and safety of explosion-proof lamps. Therefore, it is necessary to provide a more reliable, simplified manufacturing process that can fundamentally eliminate the risk of light leakage on the light guide plate's light-incident side. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a backlight module with ink brushed on the light-incident side of the light guide plate of an explosion-proof lamp and its manufacturing method. This addresses the problem of completely eliminating light leakage caused by the physical gap (Z-axis gap) between the light guide plate and the LED reflective components, improving illumination uniformity and luminous efficiency. It also enhances the structural reliability and long-term stability of the backlight module, avoiding performance degradation due to tape aging, displacement, and other issues. Furthermore, it simplifies the production process, reducing reliance on complex processes such as high-precision U-fold structures, thereby lowering production costs and improving production efficiency.

[0005] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a backlight module with ink applied to the light-incident side of a light guide plate for an explosion-proof lamp, comprising a light guide plate, wherein the improvement is that the light-incident side surface of the light guide plate is provided with a double-layer ink structure, the double-layer ink structure comprising: The lower white ink layer is directly coated on the light-incident surface of the light guide plate to efficiently reflect the light emitted by the LED that may overflow back to the light source area, thereby improving light utilization. The upper black ink layer, covering the white ink layer, is used to absorb stray light and form a tight, gapless contact with external structures (such as LED reflective surfaces) to achieve optical sealing and fundamentally block the light leakage path.

[0006] Preferably, the thickness of the white ink layer is 30-50 μm, and its reflectivity is not less than 95%; the thickness of the black ink layer is 20-30 μm, and its transmittance is not higher than 0.1%. This parameter range ensures the best balance between the reflectivity of the lower layer and the light absorption effect of the upper layer's sealing.

[0007] As a further preferred embodiment, the adhesion between the white ink layer and the light guide plate substrate is not less than 5 N / cm, and the adhesion between the black ink layer and the white ink layer is not less than 4 N / cm. This high adhesion ensures the strong bond between the ink layer and the substrate, as well as between the layers, forming a stable integrated structure.

[0008] As a further preferred embodiment, the white ink layer covers the projection area of ​​the LED light-emitting surface on the light guide plate and extends outward by 0.3 mm, with each end recessed 1 mm into the total length of the light guide plate to avoid edge interference; the black ink layer completely covers the white ink layer and extends outward by 0.1 mm on each side, with its length consistent with the total length of the light guide plate. This design ensures full coverage of potential light leakage areas and effective edge sealing.

[0009] As a further preferred option, the thickness of the ink layer can be adjusted adaptively for light guide plates made of different materials: when the light guide plate is made of PMMA, the thickness of the white ink layer is preferably 30-40μm, and the thickness of the black ink layer is preferably 20-25μm; when the light guide plate is made of PC, the thickness of the white ink layer is preferably 40-50μm, and the thickness of the black ink layer is preferably 25-30μm.

[0010] Secondly, the present invention provides a method for preparing a backlight module with ink brushed on the light-incident side of the light guide plate of the above-mentioned explosion-proof lamp, comprising the following steps: S1. Pretreatment: Clean the light-incident surface of the light guide plate to remove oil and dust; then perform low-temperature plasma treatment to activate the surface, increase its surface energy, and enhance the wettability and adhesion of the ink.

[0011] S2. Spraying the lower layer of white ink: Using precision spraying equipment, high reflectivity white ink is evenly coated onto the light-incident surface of the pretreated light guide plate, and then UV cured to form a cured white ink layer.

[0012] S3. Spraying the top layer of black ink: Using precision spraying equipment, high light-absorbing black ink is evenly coated onto the cured white ink layer, completely covering the white ink layer. Then, UV curing is performed to form a cured black ink layer, thus forming a complete double-layer ink structure.

[0013] S4. Post-processing and inspection: Perform necessary edge processing on the coated light guide plate, and test its thickness, sealing and light efficiency to ensure that the product has no light leakage, no gaps and meets the performance standards.

[0014] As a preferred preparation method, in the pretreatment step, the plasma treatment power is 50-80W, the treatment time is 10-15s, and the surface energy after treatment is increased to not less than 40mN / m.

[0015] Preferably, the white ink is applied using an automatic precision spraying machine, with the spraying pressure controlled at 0.2-0.3 MPa, the spraying distance at 15-20 cm, and the travel speed at 50-80 mm / s. The white ink is applied in two coats to achieve the target thickness and to avoid the formation of air bubbles.

[0016] Preferably, the black ink spraying uses the same equipment as the white ink spraying but with a dedicated nozzle, controlling the spraying pressure to 0.15-0.25MPa, the spraying distance to 15-20cm, and the travel speed to 60-90mm / s, using a one-time spraying method to achieve the target thickness.

[0017] Preferably, in the UV curing step, the curing energy for the white ink layer is 800-1000 mJ / cm², and the curing energy for the black ink layer is 600-800 mJ / cm².

[0018] The beneficial effects of this invention are as follows: This invention, through the integrated design of a double-layer ink structure and a light guide plate, completely eliminates the traditional Z-axis physical gap (reducing it to 0), fundamentally preventing light leakage paths. The high reflectivity of the lower white ink effectively reflects side-leaked light back to the utilization area, while the upper black ink absorbs residual stray light. With this dual protection, the illumination uniformity of the backlight module is significantly improved (up to 90% or more), with extremely low light efficiency loss, and overall brightness is increased without increasing power consumption.

[0019] In this invention, the ink layer and the light guide plate are tightly bonded together through chemical and physical methods to form a stable integrated structure. This avoids the risks of aging and detachment associated with traditional tapes, significantly extending the service life (to over 50,000 hours). The gapless sealing design also significantly improves the module's resistance to harsh environments such as dust and moisture, better meeting the high reliability requirements of explosion-proof lighting fixtures.

[0020] This invention eliminates the need for LED reflective tape and complex U-fold structures and their mounting processes, reducing the number of parts and assembly steps. The precision spraying and UV curing processes used are mature and easily automated and mass-produced, which not only improves production efficiency (by about 20%) and reduces labor costs, but also enhances product consistency, resulting in an overall reduction of production costs by 15%-20%. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a step-by-step diagram illustrating the preparation method of a backlight module with ink brushed onto the light-incident side of an explosion-proof lamp light guide plate. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This embodiment provides a backlight module for a conventional rectangular explosion-proof lamp and its preparation method. The light guide plate is made of PMMA (polymethyl methacrylate, with a light transmittance of about 92%).

[0025] 1. Structural Implementation The backlight module includes a light guide plate (LGP). On the light-incident surface of the light guide plate, a double-layer ink structure is sequentially applied: a lower white ink layer, directly coated onto the surface of the light guide plate; and an upper black ink layer, completely covering the white ink layer. The thickness of the white ink layer is controlled at 35 μm, and the thickness of the black ink layer is controlled at 22 μm. Testing showed that the white ink layer has a reflectivity of 96%, and the black ink layer has a transmittance of <0.08%. The adhesion between the white ink layer and the PMMA light guide plate reaches 5.5 N / cm, and the adhesion between the black ink layer and the white ink layer reaches 4.5 N / cm.

[0026] 2. Preparation method implementation The preparation process is as follows: pretreatment → spraying white ink → curing → spraying black ink → curing → post-treatment and testing.

[0027] Step S1: Preprocessing The light-incident side of the PMMA light guide plate was wiped clean with a lint-free cloth soaked in isopropyl alcohol (IPA) to ensure a clean surface. It was then placed in a low-temperature plasma treatment device with a power setting of 55W and a treatment time of 12 seconds. After treatment, the surface energy increased to 42 mN / m.

[0028] Step S2: Spray the lower layer of white ink Toyobo WH-8000 high-reflectivity white ink was selected. An Iwata W-61 automatic precision spraying machine (0.4mm nozzle diameter) was used. The spraying pressure was set to 0.25MPa, the spray gun distance to the workpiece was 18cm, and the travel speed was 70mm / s. Two coats were applied: the first coat was approximately 18μm thick, pre-cured with UV light (200mJ / cm²) to slightly harden the surface; the second coat was approximately 17μm thick, bringing the total thickness to 35μm.

[0029] Step S3: Curing the white ink layer The coated light guide plate was then placed into a UV curing tunnel using 365nm ultraviolet light. The curing energy was set to 850mJ / cm², and the curing time was 45 seconds. After curing, the ink layer hardness (tested with a pencil hardness tester) was 3H.

[0030] Step S4: Spray the top layer of black ink Ten strips of high-absorption black ink, model BK-700, were selected. The same spraying machine was used, but the nozzles were changed to those specifically designed for black ink. The spraying pressure was set to 0.2 MPa, the spraying distance to 18 cm, and the travel speed to 80 mm / s. A single spray coat was applied, achieving a thickness of 22 μm.

[0031] Step S5: Curing the black ink layer The material was then placed back into the UV curing tunnel, with the curing energy set at 650 mJ / cm² and the curing time at 40 seconds. After curing, the adhesion between the black ink layer and the underlying white ink layer was measured using the cross-cut adhesion test (ASTM D3359) and reached 4.8 N / cm.

[0032] Step S6: Post-processing and inspection Lightly sand the edges of the ink layer with 800-grit sandpaper to remove burrs. Confirm that the thickness of each layer meets the standard using a laser thickness gauge. Use a helium mass spectrometer to test the leak rate in a simulated sealed lamp cavity; the leak rate is 5 × 10⁻¹. 0 Pa·m³ / s, far superior to ≤1×10⁻ 9 The requirement was met by using an integrating sphere in a darkroom to test the luminous efficacy. The light leakage was measured to be only 0.05 lm, and the illumination uniformity reached 93%.

[0033] 3. Practical Application Scenarios The backlight module prepared in this embodiment can be applied to rectangular explosion-proof lighting fixtures used in petrochemical workshops. In this scenario, the environment contains flammable gases, placing extremely high demands on the sealing and spark-free nature of the lighting fixtures. This structure completely eliminates physical gaps in the optical path, not only preventing external hotspots that may result from light leakage, but its integrated ink sealing layer also enhances the overall dustproof and explosion-proof performance, meeting the safety standards required for this harsh environment.

[0034] This embodiment optimizes the implementation of a light guide plate made of PC (polycarbonate, with a light transmittance of approximately 89%), and applies it to explosion-proof lighting fixtures that require higher mechanical strength.

[0035] 1. Adjustment of structural and process parameters Because the surface properties of PC material differ from those of PMMA, their responses to ink adhesion and curing also differ. Therefore, the key parameters should be adjusted as follows: Pretreatment: The plasma treatment power was increased to 75W and the treatment time was 14 seconds, so that the surface energy reached 45mN / m.

[0036] Ink thickness: The target thickness of the white ink layer is set to 45μm, and the target thickness of the black ink layer is set to 28μm.

[0037] Curing energy: The UV curing energy of the white ink layer is increased to 950 mJ / cm², and the curing energy of the black ink layer is set to 750 mJ / cm².

[0038] Spraying area: The white ink layer covers the LED light-emitting surface projection and extends outward by 0.3mm, with each end recessed by 1mm; the black ink layer extends outward by 0.1mm on each side on the basis of the white layer, with the length consistent with the light guide plate.

[0039] 2. Effect Verification The PC light guide plate backlight module prepared according to the above parameters was tested and found to have ink layer adhesion, hardness, and sealing performance comparable to those of Example 1. Because PC itself has better impact resistance, combined with the integrated ink structure of this invention, it is particularly suitable for explosion-proof lighting equipment in environments such as mines and tunnels where mechanical collisions or vibrations may occur.

[0040] This embodiment demonstrates an implementation method suitable for small-batch, multi-model light guide plate production, showcasing the process flexibility of the present invention.

[0041] 1. Equipment and process selection Production scale: Small-batch trial production, with a daily output of approximately 50-100 pieces.

[0042] Recommended equipment: A manual screen printing machine with a programmable mobile platform and a separate UV curing light box.

[0043] Process advantages: No need to make complicated spraying fixtures; the spraying pattern can be quickly changed by adjusting the screen printing plate, adapting to the production of light guide plates of different shapes (such as round and long strips).

[0044] 2. Key process control Ink preparation: Both white and black inks are filtered through a 300-mesh screen and mechanically stirred for 10 minutes before use to ensure uniform viscosity.

[0045] Screen printing process: The wet film thickness is precisely controlled by controlling the mesh count (200 mesh for white ink and 250 mesh for black ink) and the squeegee pressure. After UV curing, the target dry film thickness is achieved (40±5μm for white ink and 25±5μm for black ink).

[0046] Curing: A staged curing process is adopted. After the white ink layer is cured, it is left to stand for 10 minutes before screen printing the black ink to reduce interlayer stress.

[0047] 3. Application Scenarios This implementation is ideal for customized, small-batch lighting of specialized explosion-proof equipment, such as ship cabin lighting and emergency command vehicle lights. It balances process cost with product performance, demonstrating that this invention is not only advantageous in automated mass production but also feasible in flexible manufacturing.

[0048] As can be seen from the above embodiments, this invention, through an integrated structural design of "light guide plate substrate—white reflective ink—black sealing ink," combined with a precise and controllable coating and curing process, reduces the Z-axis gap of approximately 0.07mm in the traditional solution to zero, cutting off the light leakage path at its structural root. The white ink layer of this invention performs the optical reflection function, while the black ink layer performs the sealing and light absorption functions, replacing multiple discrete components and processes such as the original reflective tape and structural bending. The process parameter range (such as power, pressure, energy, and thickness) and optimized solutions for different materials (PMMA / PC) provided by this invention demonstrate that the technical solution possesses sufficient reproducibility and industrial applicability. This invention eliminates the need for dedicated reflective tape and high-precision U-fold processing, simplifying the supply chain and assembly process, and reducing overall costs.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A backlight module with ink brushed on the light-incident side of the light guide plate of an explosion-proof lamp, comprising a light guide plate, characterized in that, The light guide plate has a double-layer ink structure on its light-incident side surface, the double-layer ink structure comprising: A lower white ink layer is coated on the light-incident surface of the light guide plate to reflect light; The upper black ink layer covers the white ink layer and is used for light absorption and sealing.

2. The backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 1, characterized in that, The thickness of the white ink layer is 30-50 μm, and the reflectivity is not less than 95%; the thickness of the black ink layer is 20-30 μm, and the transmittance is not higher than 0.1%.

3. The backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 1 or 2, characterized in that, The adhesion between the white ink layer and the light guide plate is not less than 5 N / cm, and the adhesion between the black ink layer and the white ink layer is not less than 4 N / cm.

4. The backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 1, characterized in that, The white ink layer is sprayed over an area that covers the LED light-emitting surface projection range by 0.3mm, and is recessed into the light guide plate by 1mm at each end; the black ink layer is sprayed over an area that completely covers the white ink layer and is extended outward by 0.1mm on each side, with a length consistent with the light guide plate.

5. The backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 1, characterized in that, The light guide plate is made of PMMA or PC, with the corresponding thicknesses of the white ink layer being 30-40μm and 40-50μm, and the thicknesses of the black ink layer being 20-25μm and 25-30μm, respectively.

6. A method for preparing a backlight module with ink brushed on the light-incident side of an explosion-proof lamp light guide plate, the method being used to prepare a backlight module with ink brushed on the light-incident side of an explosion-proof lamp light guide plate as described in any one of claims 1-5, characterized in that, Includes the following steps: The light-incident side of the light guide plate is pretreated, including cleaning and plasma activation; A layer of white ink is sprayed on and then cured with UV light to form a white ink layer. A top layer of black ink is sprayed on and then cured with UV light to form a black ink layer. Post-processing and testing are performed to ensure no light leakage and no gaps.

7. The method for preparing a backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 6, characterized in that, In the pretreatment step, the plasma treatment power is 50-80W, the treatment time is 10-15s, and the surface energy is increased to no less than 40mN / m.

8. The method for preparing a backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 6, characterized in that, The white ink is applied using an automatic precision spraying machine with a spraying pressure of 0.2-0.3 MPa, a spraying distance of 15-20 cm, and a travel speed of 50-80 mm / s. The application is completed in two stages.

9. The method for preparing a backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 6, characterized in that, The black ink spraying uses the same spraying equipment with different nozzles, a spraying pressure of 0.15-0.25MPa, a spraying distance of 15-20cm, a travel speed of 60-90mm / s, and is completed in one spraying.

10. The method for preparing a backlight module with ink brushed on the light-incident side of the explosion-proof lamp light guide plate as described in claim 6, characterized in that, In the UV curing step, the curing energy for the white ink layer is 800-1000 mJ / cm², and the curing energy for the black ink layer is 600-800 mJ / cm².

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