Deformation-informed design of dual-cure adhesives for camera modules via microscale digital image correlation

초록

As autonomous driving expands, high-performance camera modules have become essential. Dual-cure adhesives, critical for the active alignment of optical components in the modules, must ensure thermo-mechanical reliability. This study proposes a deformation-informed design of dual-curing adhesives across the entire product cycle, from chemical formulation to mechanical reliability evaluation of camera modules. Three dual-curing adhesives were formulated using diglycidyl ether of bisphenol A, with controlled epoxy-acrylate ratios, mercaptan curing agents, and OH-functionalized silica fillers. The adhesive-bonded assemblies were characterized using microscale digital image correlation, which enabled evaluation of adhesive joint deformation during early-phase, component-level reliability testing and identification of vulnerable properties and weak sites. The optimized adhesive exhibited superior performance, achieving a strength of 43.8 MPa and a cure shrinkage of 1.77 % through feedback-guided enhancement. The time to detect interfacial failure, previously requiring a month-long thermal shock test, was reduced to one hour. The developed 8-megapixel camera module passed thermo-mechanical reliability tests, maintaining a spatial frequency response change of less than 0.15 after 1,000 thermal shock cycles between-40 degrees C and 115 degrees C, as well as 164 h of high temperature-humidity testing at 85 degrees C and 85 % relative humidity.

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