Conferences and supporting programme
Plastic cover lens with multi optical surfaces for Automotive display
The expectation for the plastic cover-lens is getting bigger with increasing of the automotive display size. Because the plastic material shows great advantage for the 'Head Impact' safety. On the other hands, from the design aspects, Plastic cover-lens has still less esthetical and optical performance compare with the conventional glass cover-lens. To improve this esthetical and optical performance, DNP developed the AR transfer in-molding process and introduced double in-molding process. - Double in-molding As DNP explained” one-foil solution” in the EDC2018, with the foil transfer process, several different layers like Anti-glare, black bezel and other decoration layers can be transferred on Plastic cover-lens during the in-molding process. But with the conventional in-molding process, these layers are transferred only on the one surface of the cover-lens. On the other hands, general glass cover lens has the optical layer on the surface side, black bezel layer on the back side. Designers prefer the black bezel layer on the back side, because this depth effect of the black print can show the better esthetics. To achieve this depth effect with the in-molded Plastic cover lens, DNP introduced double in-molding process. With this double in-molding process, two transfer foil are introduced in the mold. Then, during the injection process, resin is injected from the side of the mold it means resin is injected between two transfer foils. After the in-molding process, on both side of Plastic cover-lens, two different functional layers are transfer formed. If we employ the AG transfer foil for the surface side, and the black bezel transfer layer for the back side, the molded Plastic cover lens has a black bezel transferred layer on the back surface, and can achieve the depth effect like as conventional glass cover-lens. - AR/Anti-reflection transfer in-molding process As DNP presented in the EDC2018, AG; Anti-glare transfer for the surface of the plastic cover-lens is common process, and there are several possibilities of the AG surface finishing process. In the automotive market, some OEM prefer clear or glossy surface of the cover-lens than the AG surface. But, AR in-mold transfer process is much more difficult than AG transfer molding process. The reason of the difficulties comes from the required surface flatness and uniformity of AR layer. Firstly, this surface flatness generates the problem to control the release force for the foil transfer. Secondly, to achieve the smooth optical appearance, AR layer thickness has to be uniform. This means, during the AR layer coating process on the PET carrier substrate, and also during the in-mold transfer process, AR layer thickness have to be kept uniform. To improve both problems, DNP developed special release layer between carrier foil and AR coating layer. With combination with the release layer and the coating and in-molding condition, DNP could achieve to control the release forth and the thickness of AR layer very precisely. Finally, DNP found out the possibility of AR transferred surface for Plastic cover-lens.
--- Date: 28.02.2019 Time: 14:35 - 14:55 Location: Conference Counter NCC Ost