Development Of Optical Window Device Based On Metal Mesh

Optical windows are exchange information windows when the optoelectronic devices are used to observe and detect objects.Therefore,the optical window is required to have a high transmittance in visible region.In order to prevent the electromagnetic radiation to affect the performance of the devices and radiation caused by internal devices to leak,it is therefore of great significance to enhance the electromagnetic interference shielding efficiency and keep good transmittance in visible region,simultaneously.On the other hand,in public places such as banks and airports,users are expected to protect the displayed information when reading information on the display.Aiming for dealing with above problems,this thesis proposes the metal mesh based optical window device with the narrow viewing angle characteristics,and further theoretical and experimental studies were carried out.The main contents are as follows:Firstly,by combination of the UV-imprinting,Nano-printing and selective electroplating techniques,a vacuum sputtering-free process is explored for fabrication of composite Ag-Ni metal mesh,which is economic and time-saving.The fabricated metal mesh based transparent electromagnetic shielding window exhibits superior performance,such as low sheet electrical resistance(Rs=0.07 Ω/sq),strong electromagnetic shielding performance(in X-band,shielding efficiency up to 35dB)and high light transmittance(in visible region,T>80%).Then,qualitative analysis was completed by using LightTools to generate a series of figures showing the relation between the parameters of the view-limited optical window structure(period,line width,depth)and the viewing angle.According to orthogonal experimental method,a set of parameters were obtained(period of 80 μm,line width of 10μm,and depth of 70 μm).Moreover,by means of multiple linear regression analysis,we also present a numerical model that the angle of view can be calculated by parameters.Based on the above analysis,we fabricate UV-imprinting mold of the viewing angle limited structure by photolithography.Finally,exploring UV imprinting with limited viewing angle structure,due to the high aspect ratio of the viewing angle limited structure,it is difficult to successfully imprint the structure.In the fabrication process,for the sake of successful demolding,PDMS mold was selected as the UV-imprinting mold.And plasma modification treatment was applied to modify the surface properties of PDMS mold which can eliminate the bubble defects.The narrow viewing angle electromagnetic shielding optical window device was fabricated with UV-imprinting and Nano-printing techniques.In both vertical and horizontal orientation,the device can effectively reduce the viewing angle(the viewing angle is 90 degrees),Meanwhile,it also has strong electromagnetic shielding performance.In summary,the metal mesh-based optical window device with the viewing angle limitation function proposed in this work is simple in fabrication process,and has high shielding effectiveness and narrow viewing angle.