| Popis: |
The key factors, which affect the shield effectiveness of ITO transparent conductive coating, have been analyzed in the paper. All the coatings are deposited on K9 glass substrates by electron beam evaporation technology and ion-assistant deposition (IAD) technique. And the relationships between visible transmittance, sheet resistance and shield effectiveness (reflectivity of microwave ) in 2~18GHz range have been investigated. Two kinds of electromagnetic shielding coatings have been developed. One is single-layer electromagnetic shielding coating, which is ITO coating only. The other is multi-layer electromagnetic shielding coating, which is ITO with matched antireflection coatings. The performance of electromagnetic shielding coatings is as follows: average transmittance from 425 to 675nm is 83% for the K9 substrate with the single layer electromagnetic shielding coating only, and average transmittance is 88% for the substrate with the back surface antireflection coating. Average transmittance from 425 to 675nm is 88% for the substrate with the multi-layer electromagnetic shielding coating and average transmittance is 94% for the substrate with the back surface AR coating. The average reflectivity of perpendicularly incident microwave of the best coating sample is not lower than -1.5dB, for which the frequency band is from 2GHz to 18GHz. According to MIL-675C environmental stability standards, environmental and physical durability test results, including thermal cycling test, humidity test, moderate abrasion test and salt spray fog test, etc, are also in detail presented in the paper. |
