As a core component of optical display systems, the processing precision of the surface microstructure of the light guide plate directly affects light transmission efficiency and uniformity. During processing, a systematic precision control system must be constructed from seven dimensions: equipment selection, process control, material matching, environmental management, detection feedback, structural optimization, and process innovation, to minimize light loss and improve the optical performance of the light guide plate.
Selecting high-precision processing equipment is the primary condition for controlling the precision of the microstructure. Femtosecond laser processing technology, due to its extremely short pulse width and high energy density, can achieve non-thermal processing, avoiding material deformation caused by thermal damage, thereby forming micron- or even nanometer-scale microstructures on the surface of the light guide plate. This technology, through precise control of laser parameters and processing paths, can engrave complex structures such as micro-dimples, micro-hole arrays, and micro-grooves, providing a foundation for the directional propagation of light. Furthermore, single-point diamond machining technology, through point-to-point turning with natural single-crystal diamond tools, can achieve nanometer-level surface roughness, suitable for processing concave and convex lenses for light guide plates with extremely high precision requirements.
Fine control of process parameters is a key step in reducing light loss. In laser processing, parameters such as laser focal position, pulse energy, and scanning speed need to be optimized based on the characteristics of the light guide plate material. For example, an excessively deep focal spot may cause overheating at the bottom of the microstructure, leading to material carbonization; insufficient pulse energy may result in insufficient engraving depth, affecting light reflection. In injection molding, parameters such as mold temperature, injection pressure, and holding time need precise control to ensure that the microstructure completely replicates the mold morphology during molding, avoiding structural deformation caused by uneven shrinkage.
The matching of materials and processes is crucial to the precision of microstructures. Different light guide plate materials (such as PMMA, PC, and glass) have different optical properties and processing performance. For example, glass light guide plates have high refractive index and excellent chemical stability, but are difficult to process, requiring special processes (such as UV ink imprinting) to form microstructures on the surface; while PMMA light guide plates can be efficiently processed through laser engraving or injection molding. When selecting materials, factors such as optical performance, processing cost, and production efficiency must be comprehensively considered to ensure a perfect match between materials and processes.
The stability of the processing environment is an external condition for ensuring the precision of microstructures. Environmental factors such as temperature, humidity, and vibration can interfere with processing equipment, leading to processing errors. For example, temperature fluctuations can cause thermal drift in laser processing equipment, affecting the focal point; excessive humidity can cause moisture to adsorb onto the material surface, affecting the interaction between the laser and the material. Therefore, processing workshops need to be equipped with constant temperature and humidity systems and vibration reduction measures to provide a stable environment for high-precision processing.
Post-processing inspection and feedback are the closed-loop links for optimizing microstructure accuracy. Using equipment such as optical microscopes and atomic force microscopes to inspect the morphology, size, and roughness of microstructures allows for timely detection of processing defects, which can be corrected by adjusting process parameters. For example, if burrs are found at the edges of the microstructure, this can be improved by optimizing the laser scanning path or adding post-processing steps (such as chemical etching). Furthermore, simulating the optical properties of the microstructure using optical simulation software can predict the propagation path of light within the light guide plate, providing a theoretical basis for structural optimization.
The rationality of microstructure design is an intrinsic factor in reducing light loss. By optimizing the shape, size, and arrangement of the microstructure, light can be guided to propagate along a predetermined path, reducing scattering and reflection losses. For example, a gradient dot design, where the microstructure density gradually increases from the light source to the distal end, achieves uniform light distribution. Utilizing the high refractive index of glass microspheres creates multiple reflections and refractions within the light guide plate, improving light energy utilization. Furthermore, customized dot layouts can be designed to meet the needs of different application scenarios, such as uniform or varying sizes, satisfying both common and specific requirements.
Process innovation is the core driving force behind improving the precision of light guide plate microstructure processing. With technological advancements, new processing methods are constantly emerging. For instance, photopolymer microimprinting technology leverages the rapid curing characteristics of photopolymer materials to achieve efficient, environmentally friendly, and low-cost microstructure replication; UV ink imprinting technology prints low-refractive-index UV inks onto the glass light guide plate surface and then uses an imprinting roller to carve V-grooves, achieving high-brightness, low-cost microstructure processing. These innovative processes provide more options for light guide plate microstructure processing, driving continuous improvement in light guide plate performance.
