Antireflection coatings on plastics deposited by plasma polymerization process

Abstract

Abstract. Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage processexposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

Comparison of Surface Modification of CR-39 Polymer Film Using RF and DC Glow Discharges Plasma

“…With the applied energy, various bonds on the polymer surface will break, and then they are ready to form bonds with ad atoms [11].…”

“…Srivatsa et al 2008 [11] developed fabricated deposition system, for depositing fairly hard, durable and efficient antireflection coatings on polycarbonate substrates. The process involves making the normally hydrophobic surface of the polycarbonate substrate (CR-39) wettable, followed by the deposition of a surface-hardening layer of carbonyl silica, and finally the deposition of a four-layer antireflection coating comprising alternating layers of silicon dioxide and titanium dioxide, of specified thicknesses.…”

Growth and characterization of MMA/SiO2 hybrid low-k thin films for interlayer dielectric applications

“…Hence, FTIR spectra validate the formation of homogenous matrix of organic MMA and SiO 2 hybrid film. The keen observation of spectra clearly shows the increase in broadness of Si-O-Si stretching peak, that is because of formation of Si-O-C bonds (Srivatsa et al 2008) overlapped in 1000-1200 cm -1 . Table 1 explains different bonds present in film at specific wavenumbers with variations of MMA.…”

A Comparative Study of Adhesion Evaluation Methods on Ophthalmic AR Coating Lens

“…Usually, one or more thin films deposit sequentially on lens surface to form AR coating. By destructive interference between the light waves reflected from the surfaces and interfaces of thin films, an AR coating reduces the reflected light intensity for better transparency as well as vision [9]. The vast majority of commercial AR coatings on ophthalmic lenses are produced by physical vapor deposition (PVD) techniques [10,11].…”