Flexible and stretchable Micro-LED array devices with Optical-Thermal layered packaging
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摘要:
针对柔性可拉伸微型LED阵列器件在高电流密度下热积累严重，以及传统导热填料易导致有机硅基体固化抑制的难题，本文提出一种基于铂金催化改性的光热分层封装结构，构建了集基底层散热反射、中层蛇形导电互连LED阵列及顶层透光功能于一体的4×4柔性可拉伸LED阵列。基底层采用AlN颗粒作为导热填料，并引入铂金催化剂作为固化补偿剂，实现了填充量20 wt%、粒径60 μm的AlN在Ecoflex 00-30基体中均匀分散与完全固化。实验表明，AlN/Ecoflex 00-30复合基底材料具备良好的热学与力学性能，其热导率达0.222 W/(m·K)，较纯Ecoflex 00-30提升了35.4%，且在300%的拉伸应变下仍保持结构完整。通过将高柔韧性的基底层与高拉伸度蛇形导电互连结构结合，有效释放了机械形变过程中的应力，保障了器件在动态弯曲下的电学连接可靠性。瞬态热阻测试表明，采用光热分层封装的LED发光单元在20 mA恒定驱动电流下的稳态结温较纯Ecoflex 00-30封装降低2.95 °C。验证了该方案在协同实现热管理与力学顺应性的可行性。
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关键词:
- 柔性微型LED封装 /
- AlN/Ecoflex 00-30复合材料 /
- 蛇形导电互连 /
- 瞬态结温测试
Abstract:Flexible and stretchable micro-LED arrays suffer from severe heat accumulation at high current densities. Conventional thermally conductive fillers can also inhibit curing of silicone matrices. We propose a platinum-catalyst-modified optical-thermal layered packaging structure to address both problems. A 4 × 4 flexible and stretchable LED array was fabricated. It integrates a heat-dissipating and light-reflecting substrate layer. The middle layer contains an LED array with serpentine conductive interconnects. A light-transmitting functional layer forms the top layer. AlN particles were used as thermally conductive fillers in the substrate. Additional platinum catalyst was introduced as a curing compensator. Uniform dispersion and complete curing were achieved at 20 wt% loading and 60 μm particle size. The composite substrate showed favorable thermal and mechanical properties. Its thermal conductivity reached 0.222 W/(m·K), 35.4% higher than pristine Ecoflex 00-30. It remained structurally intact under 300% tensile strain. The flexible substrate and serpentine interconnects effectively released stress during mechanical deformation. They maintained reliable electrical connections under dynamic bending. Transient thermal resistance tests were conducted at a constant driving current of 20 mA. The steady-state junction temperature was 2.95 °C lower than that of pristine Ecoflex 00-30 packaging. These results demonstrate effective thermal management while maintaining mechanical compliance.
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图 1 光热分层柔性可拉伸微型LED阵列结构示意图。(a)4×4阵列正视图；(b)器件结构分解图
Figure 1. Schematic of the optical-thermal layered flexible and stretchable micro-LED array. (a) Front view of the 4 × 4 array; (b) three-dimensional structure of the device
图 2 AlN/Ecoflex 00-30复合材料光学显微图。(a)未添加固化补偿剂；(b)添加固化补偿剂
Figure 2. Optical micrographs of AlN/Ecoflex 00-30 composites. (a) Without curing compensator; (b) With curing compensator
图 3 李氏盘稳态热导率测试系统结构示意图
Figure 3. Schematic of the Lee's disk steady-state thermal conductivity measurement system
图 4 1 μm粒径AlN填料不同质量分数下 AlN/Ecoflex 00-30 复合基底热导率测试结果
Figure 4. Thermal conductivity of AlN/Ecoflex 00-30 composite substrates at different AlN mass fractions using 1 μm AlN fillers
图 5 固定20 wt%质量分数下不同AlN粒径AlN/Ecoflex 00-30复合基底热导率测试结果
Figure 5. Thermal conductivity of AlN/Ecoflex 00-30 composite substrates with different AlN particle sizes at a fixed mass fraction of 20 wt%
图 6 单轴拉伸。(a)试样几何尺寸参数(单位：mm)；(b)制备的实体试样
Figure 6. Uniaxial tensile test. (a) Geometric dimensions of the specimen (unit: mm); (b) photograph of the prepared specimen
图 7 多周期循环单轴拉伸测试结果。(a)-(d)分别对应第1次、第5次、第20次及第50次循环加载过程中的应力-应变迟滞曲线；(e)单轴拉伸初始状态；(f)单轴拉伸300%状态
Figure 7. Multi-cycle uniaxial tensile test results. (a)-(d) Stress-strain hysteresis curves for the 1st, 5th, 20th, and 50th cycles, respectively; (e) initial state of the specimen; (f) specimen at 300% tensile strain
图 8 柔性可拉伸微LED阵列的制备工艺流程
Figure 8. Fabrication process flow for the flexible and stretchable micro-LED array
图 9 柔性LED阵列器件与发光状态（a）柔性LED阵列器件图；（b）阵列点亮图；（c）单折叠发光图；（d）双折叠发光图；（e）锥状形变发光图
Figure 9. Flexible LED array device and its light-emitting states. (a) Flexible LED array device; (b) illuminated array; (c) light emission under single folding; (d) light emission under double folding; (e) light emission under conical deformation
图 10 基于“双面主动加热-热阻尼缓冲-中心均温”架构的柔性器件固态K因子标定系统原理图
Figure 10. Schematic of the solid-state K-factor calibration system for flexible devices based on "bilateral active heating, thermal damping buffering, and central temperature equalization"
图 11 LED的正向电压-结温（
$ {V}_{f}-{T}_{j} $ ）标定拟合曲线Figure 11. Calibration and fitted curves of LED forward voltage versus junction temperature (
$ {V}_{f}-{T}_{j} $ )
图 12 方波扫描热-电耦合瞬态测温原理与时序控制逻辑图
Figure 12. Schematic of the principle and timing control logic for square-wave scanning thermo-electric coupled transient temperature measurement
图 13 不同基底封装材料发光单元的热-电耦合测试结果对比
Figure 13. Comparison of thermo-electric coupled test results for LED devices with different substrate encapsulation materials
图 14 不同基底封装材料发光单元达到热学平衡后的稳态结温（
$ {T}_{j} $ ）与净温升（$ \text{Δ}T $ ）Figure 14. Steady-state junction temperature (
$ {T}_{j} $ ) and net temperature rise ($ \text{Δ}T $ ) of LED devices with different substrate encapsulation materials after reaching thermal equilibrium
图 15 不同基底封装材料LED发光单元连续工作过程中的平均峰值波长变化。阴影区域表示5次测试结果的标准差
Figure 15. Variation of average peak wavelength for LED units with different substrate packaging materials during continuous operation. The shaded area represents the standard deviation of five measurements.
表 1 LED阵列器件封装散热基底层和未封装5次光功率密度测试结果(单位：
$ \text{mW/}{\text{cm}}^{2} $ )Table 1. Five optical power density measurements of the LED array device with and without heat-dissipating substrate encapsulation (unit: mW/cm2)
1 2 3 4 5 平均值 封装 2.0406 2.0347 2.0312 2.0317 2.0339 2.03442 未封装 1.7641 1.7595 1.7583 1.7622 1.7548 1.75978 
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[1] JIANG Q H, ANTWI-AFARI M F, FADAIE S, et al. Self-powered wearable Internet of Things sensors for human-machine interfaces: a systematic literature review and science mapping analysis[J]. Nano Energy, 2024, 131: 110252. doi: 10.1016/j.nanoen.2024.110252 [2] 李继军, 聂晓梦, 李根生, 等. 平板显示技术比较及研究进展[J]. 中国光学, 2018, 11(5): 695-710. doi: 10.3788/CO.20181105.0695LI J J, NIE X M, LI G SH, et al. Comparison and research progress of flat panel display technology[J]. Chinese Optics, 2018, 11(5): 695-710. (in Chinese). doi: 10.3788/CO.20181105.0695 [3] 冯思悦, 梁静秋, 梁中翥, 等. LED微阵列投影系统设计[J]. 中国光学, 2019, 12(1): 88-96. doi: 10.3788/CO.20191201.0088FENG S Y, LIANG J Q, LIANG ZH ZH, et al. Design of projection system for a micro-LED array[J]. Chinese Optics, 2019, 12(1): 88-96. (in Chinese). doi: 10.3788/CO.20191201.0088 [4] 李香兰, 金霞, 吕金光, 等. Micro LED车灯投影光学系统设计与优化[J]. 中国光学(中英文), 2024, 17(1): 89-99. doi: 10.37188/CO.2023-0063LI X L, Jin X, LV J G, et al. Design and optimization of Micro LED vehicle light projection optical system[J]. Chinese Optics, 2024, 17(1): 89-99. (in Chinese). doi: 10.37188/CO.2023-0063 [5] WANG CH X, YU Q, ZHANG X C, et al. Flexible, implantable, and wearable LED devices based on the perspective of photomedicine: progress and potential medical applications[J]. Materials Today, 2025, 88: 752-782. doi: 10.1016/j.mattod.2025.06.015 [6] LEE J H, KIM M S, LEE S H, et al. Flexible, surface-lighting MicroLED skin patch for multiple human skincare[J]. Biomaterials, 2025, 318: 123139. doi: 10.1016/j.biomaterials.2025.123139 [7] LIU ZH Y, CAO H CH, TANG X, et al. Advanced technologies in InGaN micro-LED fabrication to mitigate the sidewall effect[J]. Light: Science & Applications, 2025, 14(1): 64. doi: 10.1038/s41377-025-01751-y [8] 邝海, 黄振, 熊志华, 等. 氮化镓基Micro-LED侧壁对外量子效率的影响及侧壁处理技术综述[J]. 中国光学(中英文), 2023, 16(6): 1305-1317. doi: 10.37188/CO.2023-0091KUANG H, HUANG ZH, XIONG ZH H, et al. A review of the effect of GaN-Based Micro-LED sidewall on external quantum efficiency and sidewall treatment techniques[J]. Chinese Optics, 2023, 16(6): 1305-1317. (in Chinese). doi: 10.37188/CO.2023-0091 [9] LIM M S, JEONG E G. Developments and future directions in stretchable display technology: materials, architectures, and applications[J]. Micromachines, 2025, 16(7): 772. doi: 10.3390/mi16070772 [10] PAN K L, WANG J, LI Y, et al. Sandwich-like flexible breathable strain sensor with tunable thermal regulation capability for human motion monitoring[J]. ACS Applied Materials & Interfaces, 2024, 16(8): 10633-10645. doi: 10.1021/acsami.3c16607 [11] 吴福培, 谢晓扬, 李昇平. 一种散热型发光二极管阵列结构光源设计方法(英文)[J]. 中国光学, 2021, 14(3): 670-684. doi: 10.37188/CO.2020-0211WU F P, XIE X Y, LI SH P. A thermal dissipation design method for LED array structure illumination[J]. Chinese Optics, 2021, 14(3): 670-684. (in Chinese). doi: 10.37188/CO.2020-0211 [12] PARBROOK P J, CORBETT B, HAN J N, et al. Micro-light emitting diode: from chips to applications[J]. Laser & Photonics Reviews, 2021, 15(5): 2000133. doi: 10.1002/lpor.202000133 [13] LI Z T, TAN J, LI J SH, et al. A review on thermal management of light-emitting diodes: from package-level to system-level[J]. Applied Thermal Engineering, 2024, 257: 124145. doi: 10.1016/j.applthermaleng.2024.124145 [14] WEI Y, LIAO Y M, LAI X J, et al. Synergistically improving tracking resistance of addition-cure liquid silicone rubber with aminepropyltriethoxysilane-immobilized silica and platinum catalyst[J]. Silicon, 2024, 16(15): 5681-5689. doi: 10.1007/s12633-024-03108-3 [15] JIAO R, WANG R Q, XU Q, et al. Highly stretchable strain-insensitive vertical serpentine conductors for flexible electronics[J]. IEEE Sensors Journal, 2025, 25(8): 13810-13818. doi: 10.1109/JSEN.2025.3545952 [16] YE CH, STEWART B G, SITARAMAN S K. Stretchability of serpentine interconnect on polymer substrate for flexible electronics: a geometry and material sensitivity analysis[C]. 2020 IEEE 70th Electronic Components and Technology Conference (ECTC), IEEE, 2020: 1533-1541. [17] MATSUMOTO N, FUTABA D N, YAMADA T, et al. Enhancing the thermal conductivity of CNT/AlN/silicone rubber composites by using CNTs directly grown on AlN to achieve a reduced filler filling ratio[J]. Nanomaterials, 2024, 14(6): 528. doi: 10.3390/nano14060528 [18] WANG J J, YI X S. Effects of interfacial thermal barrier resistance and particle shape and size on the thermal conductivity of AlN/PI composites[J]. Composites Science and Technology, 2004, 64(10-11): 1623-1628. doi: 10.1016/j.compscitech.2003.11.007 [19] ASTM International. ASTM D5470-17 Standard test method for thermal transmission properties of thermally conductive electrical insulation materials[S]. West Conshohocken: ASTM International, 2017. [20] ASTM International. ASTM D412-16 Standard test methods for vulcanized rubber and thermoplastic elastomers-tension[S]. West Conshohocken: ASTM International, 2016. (查阅网上资料, 不确定本条文献年份, 请确认). [21] JEDEC Solid State Technology Association. JESD51-1 Integrated circuit thermal measurement method-electrical test method (single semiconductor device)[S]. Arlington: JEDEC, 1995. [22] XI Y, SCHUBERT E F. Junction-temperature measurement in GaN ultraviolet light-emitting diodes using diode forward voltage method[J]. Applied Physics Letters, 2004, 85(12): 2163-2165. doi: 10.1063/1.1795351 -
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