扩展微透镜数值孔径范围的阶梯光刻热熔法研究

Step HeatForming Photoresist Method for Expanding the N.A.Rangeof Refractive Microlens

在微透镜阵列的光刻热熔制作法中，临界角效应严重影响了微透镜的制作范围和面形质量。在对临界角效应定性研究的基础上，提出了用阶梯光刻热熔法来扩展热熔型微透镜阵列的数值孔径范围。实验结果表明，采用这一方法制作的微透镜，其单元孔径范围扩展为５０～９００μｍ，相对口径范围扩大到为Ｆ／１～Ｆ／１０，并有效地改善了临界角效应对大孔径微透镜面形质量的影响。

The existence of critical angle seriously limits the range of microlens array′s numerical aperture and the improvement of the quality of the microlens in the fabrication of microlens array by using heatforming photoresist method. Based on the study of the critical angle effect, a new method named step heatforming photoresist method to expand the N.A. range of microlens array is presents. The results show that this method can effectively improve the conventional heatforming fabrication. The available diameter range of microlens is from 50 μm up to 900 μm. A series of MLA with F/1 to F/10 relative apertures have been fabricated, with the improved quality of the profile.