环烯烃共聚物表面减反膜的制备及其可靠性研究

Preparation and Reliability of Anti-Reflection Film on Cyclic Olefin Copolymer Surface

高分子材料以其优异的性能,近年来得到了广泛的应用。以一种新型高分子材料环烯烃共聚物为基底,设计并研制了400~700 nm波段的减反射膜。根据薄膜热应力理论分析了材料特性,选择ZrO_(2)作为黏结层,研究了等离子体处理时间对基底表面微观结构以及化学组成的影响。通过优化工艺参数和增加基底表面的活性,提高了基底与黏结层的结合力,再通过过渡层将黏结层与镀层结合,解决了薄膜与基底热膨胀系数不匹配的问题。采用镀后离子束轰击技术解决了恒温恒湿时的膜裂问题。测试结果表明,减反射膜在400~700 nm波段的平均反射率为0.117%,且具备良好的耐环境性能。

Objective Cyclic olefin copolymer(COC)is a kind of amorphous polymer material which attracts more and more attention in recent years,and it has many advantages such as high transmittance covering the full spectrum,low birefringence coefficient,very low water absorption,low density,not fragile,high Abbe number,stable chemical properties,acid and alkali resistance,and excellent mechanical properties.Compared with traditional transparent plastics such as polymethyl methacrylate(PMMA)and polycarbonate(PC),COC not only has the same optical performance as PMMA,but also has higher temperature resistance than it.And these characteristics are the excellent properties needed for the preparation of optical elements.Therefore,COC is considered as an ideal substitute material for PC,PMMA,polystyrene,polyvinyl chloride,and some engineering plastics,and has a good development prospect in the optical field.However,COC is similar to traditional polymer materials due to its high coefficient of thermal expansion,and thus film cracking or shedding occurs due to the temperature change during or after film coating.There are many domestic and foreign researches on the deposition of optical films on the surface of PC and PMMA,but there are few reports on the use of COC as the substrate,although COC has good performances in the visible band.Therefore,this paper mainly designs and develops the anti-reflection film for the band of 400-700nm,and conducts researches on how to improve the adhesion and environmental resistance of optical films on the COC surface.Methods The material characteristics are analyzed according to the thin film thermal stress theory,and the ZrO_(2) with the smallest thermal stress is selected as the adhesive layer by calculating the thermal stress between the first layer material and the substrate.The plasma treatment time of the substrate surface is studied.The XPS test is performed on the surface of the treated sample to find a solution with a relatively high surface oxygen content,and the technological parameters are optimized to solve the problem of film shedding due to the mismatch between the coefficients of thermal expansion of the film and the substrate.It is found that the film layer of the sample after the film pulling test is not completely fell off.Firstly,the shedding position from the spectral curve of the sample is analyzed,and then through the analysis of the moment of film,the transition layer is coated,which improves the adhesion between the coating and the adhesive layer.Finally,the samples with the two structures are tested by SEM.Through the analysis of the micrograph of the film cracking sample after the constant temperature and humidity test,it is found that the film layer is not compact enough,which causes the water vapor to enter the film layer during the test and to change the stress,and the technology of ion beam bombardment after coating is used to increase the film filling density.Results and Discussions The effect of plasma treatment under different time on the content of chemical elements and functional groups on the surface of the substrate is studied(Fig.4),and the technological parameters are optimized to increase the activity of substrate surface and improve the adhesion between the substrate and the coating.The thermal stresses of different materials with COC as the substrate are analyzed(Table 2),and the ZrO_(2) with the smallest thermal stress is selected as the adhesive layer,which solves the problem of film shedding due to the mismatch between the coefficients of thermal expansion of the film and the substrate.The film layer of the shedding sample is analyzed by the moment of film,and the adhesive layer L5is coated in the middle,so that the film layers can infiltrate and form chemical bonds on the basis of moment matching(Fig.7),which greatly improves the adhesion between the film layers.The technology of ion beam bombardment after coating solves the problem of low film aggregation density caused by non-heating in the film formation process(Table 6),and makes the sample pass the constant temperature and humidity test.Conclusions In this paper,the cyclic olefin copolymer is used as the substrate to study the properties of the substrate and the film material.And ZrO_(2) is selected as the adhesive layer and the surface of the substrate is treated with plasma to improve the adhesion between the film and the substrate.Then the moment between the film layers is analyzed and the L5is selected as the transition layer material to combine the adhesive layer with the coating,so that the film layers can infiltrate and form chemical bonds on the basis of moment matching,which greatly improves the adhesion between the film layers.The technology of ion beam bombardment after coating solves the problem of film cracking in the constant temperature and humidity test due to the non-compact film layer.The test results show that the average reflectivity of the anti-reflection film at 400-700nm is 0.117%.Furthermore,the anti-reflection film can pass the film adhesion test,the high and low temperature test,and the constant temperature and humidity test,and possesses good environmental adaptability.