목적: ITO 박막과 발수 박막의 두께에 따른 안경렌즈 투과율 변화를 관찰하고자 한다.
방법: Electron beam evaporation 와 dipping장비로 ITO 코팅, 발수 코팅, SiO2, ZrO2, 하드 코팅 막 을 제작하고 분광광도계와 ellipsomter를 이용하여 파장에 따른 광학상수를 구했다. 이러한 데이터를 이용 하여 Macleod 프로그램으로 ITO 박막과 발수 박막의 두께에 따른 안경렌즈 투과율의 변화를 관찰하였다. 박막설계는 [air / repellent film / ITO / SiO2-ZrO2-SiO2-ZrO2 / AR coating / hard coating(1.553) / lens(1.56)] 와 같다.
결과: ITO 박막과 발수 박막이 없을 시 최적 투과율은 400nm에서 700nm 까지의 평균 투과율은 약 99.5%이다. 안경렌즈 전 후면에서의 반사율이 비슷하므로 안경렌즈 전체 투과율은 약 99%이다. 발수 박막 의 두께를 고정시키고 ITO 박막의 두께를 증가시키면 가시광선의 단파장 영역의 투과율이 장파장에 비해 많 이 감소된다. ITO 박막을 고정시키고 발수 박막의 두께를 증가시킬 경우 장파장의 투과율이 감소하고 단파 장의 투과율은 발수 박막의 두께가 50nm 까지 감소하다가 그 이후에서는 투과율이 증가한다.
결론: ITO 박막의 두께를 증가시키면 가시광선의 단파장 영역의 투과율이 장파장에 비해 많이 떨어지고, 발수 박막의 두께를 증가시킬 경우 장파장의 투과율이 감소하고 단파장의 투과율은 발수 박막의 두께가 50nm 까지 감소하다가 그 이후에서는 투과율이 증가한다.

Purpose:This study is to observe transmittance changes with the thicknesses of ITO and waterrepellent films of Ophthalmic lens.Method:ITO, water-repellent, SiO2, ZrO2, hard coating films were coated by electron beam evaporation or a dipping apparatus. The refractive index and extinction coefficient of them with wavelength were obtained using spectrophotometer or ellipsometer. With these data, we observed the changes of transmittances depending on the thicknesses of ITO and water-repellent films of a flat Ophthalmic lens using the Essential Macleod program. The multilayer was designed as [air/ water-repellent film/ ITO/ AR coating multilayer(SiO2, ZrO2) / hard coating(1.553)/ lens(1.56)].Result:The optimum average transmittance in the absence of ITO and water-repellent films was about 99.5% from wavelength 400 nm to 700 nm. Since the reflectance at the front and back of a flat Ophthalmic lens was similar, the total average transmittance of the lens was about 99%. When the thickness of ITO film was increased at fixing the thickness of water-repellent film, the transmittance of the visible light in the short wavelength was much decreased with compared to that of the long wavelength. When the thickness of the water-repellent film was increased at fixing the thickness of ITO thin film, the transmittance of the long wavelength was decreased. The transmittance of the short wavelength was also decreased up to 50nm thickness, and then increased above that.Conclusions:When the thickness of ITO film was increased, the transmittance in the short wavelength was much decreased than that of the long wavelength. When the thickness of water-repellent film was increased, the transmittance of the long wavelength was decreased while the transmittance of the short wavelength was decreased up to 50nm thickness but increased above that.

• Moon Chan Park(Dept. of Ophthalmic Optics, Shinhan University) | 박문찬