It is an object of the present invention to suppress an influence of voltage drop due to wiring resistance to make an image quality of a display device uniform. The process for producing the same is characterized in that a water-soluble film forming agent optionally together with a powder vehicle is dissolved andor dispersed in water, subsequently a volatile oily antibacterial substance optionally together with an emulsifying agent is added to the solution and emulsified, and thereafter the obtained emulsion is spray dried into powder. The isolator comprises a flexible printed circuit material that includes a strain gauge. The surface of the multilayer film has an irregular surface profile, relative to the surface profile of the base. The joining of the first and second coupling units provides a mechanical support and electricity to the LED.