Optics and Precision Engineering, Volume. 32, Issue 9, 1371(2024)
Micro-optical illumination properties of hierarchical microlens arrays formed by hot-embossing
In LED lighting, glare from uneven light distribution, along with ultraviolet and blue light, can lead to visual fatigue and eye damage. Currently, adjustments are primarily made to the light source, and modifying the surface structure at the nanoscale is costly. To address this, a microscope-scale hierarchical microlens array light guide plate (LGP) has been developed using hot-embossing rapid prototyping technology to examine the impact of the scale of hierarchical microlenses on health lighting. The study first analyzes the relationship between the microlens aspect ratio and the distribution of the reflected electric field on the surface of the microprism. It then explores how the microstructure parameters of the LGP affect diffuse and specular reflection, as well as transmission. The study further compares the effects of the microscale of hierarchical microlenses on micro-optical properties such as illuminance and uniformity with existing market solutions like screen-printed microdots and microprism arrays. Findings indicate that the reflected light monitoring surface for ultraviolet and blue light shows a smaller variation in the reflection electric field when the microlens aspect ratio is between 0.6-1, suggesting higher diffuse reflection. Experiments demonstrate that the hierarchical microlens array LGP, with microlens heights of 5-30 μm and microprism heights of 10-80 μm, can be produced in just 4 seconds. Illuminance uniformity improves as the microlens aspect ratio increases, with illuminance 45% and 83% higher than that of the microprism and screen-printed microdot, respectively. Moreover, compared to the microprism, the diffuse reflectance of ultraviolet and blue light is 8% and 18% higher, respectively, and the mirror reflectance is 80%⁃83% lower. Thus, controlling the aspect ratio of the hierarchical microlens can effectively reduce lighting glare and mitigate the effects of ultraviolet and blue light.
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Manfeng HU, Lei LI, Jin XIE. Micro-optical illumination properties of hierarchical microlens arrays formed by hot-embossing[J]. Optics and Precision Engineering, 2024, 32(9): 1371
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Received: Oct. 27, 2023
Accepted: --
Published Online: Jun. 2, 2024
The Author Email: XIE Jin (jinxie@scut.edu.cn)