基于金属光子晶体的透明屏蔽膜

Transparent Shielding Film Based on the Metallic Photonic Crystal

金属网栅和氧化铟锡（ITO）等透明导电膜是实现电磁屏蔽和可视兼容的常用材料,但其屏蔽和可见光透射率受到了很大的限制。通过解决屏蔽、导电与可视性能相互制约的矛盾,可有效提高电磁屏蔽与可视性能的兼容性。为此,报道了一种金属光子晶体透明膜。采用磁控溅射制备了ITO/Ag为周期的金属光子晶体透明膜,研究了周期结构对样品屏蔽效能、透射率和方阻的影响。研究表明,随着单位周期金属膜厚的增加,可见光600~800 nm波段透射率降低10%以上,可见光透射光谱变窄。同时400~600 nm波长范围内透射率并没有随金属膜厚的增加而降低,甚至升高。随着单位周期金属膜厚增加,微波频段的屏蔽效能相应提高,方阻相应降低。实验证实：光子晶体膜的屏蔽效能与光子晶体中总金属膜厚不存在明确的因果关系,而是与＂金属-电介质＂的纳米周期结构相关。制备了一种屏效高达70dB,方阻低达2.1Ω,透射率大于50%的光子晶体膜。

Shielding effectiveness and optical transmittance are conflict in the preparation process of electro magnetic（EM） shielding and transparent film by indium tin oxide（ITO） film and metal mesh.Thus the compatibility of shielding effectiveness and light transmittance can be improved by the solution of the conflict among metal shielding,conductive and transparent.Transparent shielding film based on the metallic photonic crystal is proposed and experimentally demonstrated.The ITO/Ag periodic structured metallic photonic crystal transparent film is prepared by magnetron sputtering.The influences of the shielding effectiveness（SE）,optical transmittance and the sheet resistance on the samples are studied.With the increasing of unit cycle metal film thickness,optical light transmittance in 600~800 nm wavelength is reduced by more than 10%.At the same time,the optical transmission spectra becomes narrower.But the light transmittance in 400~600 nm wavelength does not decrease with the increasing of metal film thickness,and even increased.With the increase of metal film thickness,shielding effectiveness is improved in microwave,sheet resistance reduces.Through the experiment,a different conclusion is drawn that the photonic crystal film shielding effectiveness does not totally depend on photonic crystal metal film thickness.The results show that the shielding effectiveness is as high as 70 dB,optical transmittance is greater than 50%,sheet resistance is lower to 2.1Ω.