Design And Manufacture The Aspherical Spectacle Lens

The traditional spherical spectacle lens make wearers feel uncomfortable, because the wearers have bad vision on the edge and the lens is too thick and weight. The designers mention that the aspherical lens which will stand for spherical lens can help the man of bad vision to get clear vision.Compared with the spherical lens of same diopter, the aspherical lens can reduce the aberrations. The aspherical lens is more light and thin because of the need to address the comfort and cosmetic. In addition, the aspherical lens makes the off-axis effective diopter stable, minimize the off-axis aberration and distortion.First, we analyze the eyes and introduce the requirements of the market, and then build the surface with the merit function composing diopter, astigmatism, thickness, distortion, and field curvature, in addition, the surface is described with high order aspherical equation based on parabola. With this method, we can get the surface with proportional diopter and astigmatism, and the distortion and the field curvature can fit the tolerance of the eyes. In addition, we advanced that the surface of good smoothness is easy for mass manufacture.Then, glass mould can be produced with two different processes like classical process and heating molding. The classical polishing method can make precision surface but can't get good surface quality while the heating molding method can get good surface quality but can't get high precision surface. The mould made by heating mold can use for a long time.At last, the inspection method of the aspherical lens was introduced.The aspherical lens has been taken by the market and accepted by the users. However, the wearer is always right.