Effects of interface thermal resistance on surface morphology evolution in precision glass molding for microlens array

To study the effects of the interface thermal resistance on surface morphology evolution in precision glass molding (PGM) for microlens array with different mold materials, including Tungsten carbide and heat-resistant stainless steel, the glass-mold interface thermal resistance is calculated, and heat-transfer simulation of PGM based on an interface thermal resistance model at the heating stage is conducted correspondingly. The effect of flattening behavior on the glass-mold interface is explained. Then, experiments evaluating the relationship between heating time and glass surface roughness are carried out, and the glass adhesion phenomenon appearing on the heat-resistant stainless steel mold is observed and analyzed. Finally, the microlens array is fabricated on the nickel phosphorous plating layer on the heat-resistant stainless steel substrate by diamond-ball nose-end milling, and experiments of PGM for the microlens array are carried out to verify the interface thermal resistance model. The result shows that a high-quality surface can be obtained by the combination of a smooth mold and rough glass. Compared with the microlens array fabricated with the rough glass preform, using the smooth glass preform achieves higher form accuracy without defects or blurs.