Research On The Surface Error And Imaging Quality Of Aspheric Lens

In recent years, the aspheric lens is widely used because of its superiority to the spherical lens, but the manufacture and inspection is much more difficult. In this research, the data of the aspheric lens surface is simulated according to the precision measurement machine. A method of imaging quality evaluation which is based on the curve fitting and ray tracing is summarized as well as several parameters. First, a smooth curve is obtained from the data by curve fitting with the method of non-linear least squares fit. Then the tangent vector and the radius of curvature of each point on the curve can be calculated for the error evaluation. With the fitted curve, the focusing state of the aspheric lens can be obtained by the method of ray tracing.The main work of the research is as follows:1. The manufacture and evaluation methods of the aspheric lens are analyzed including their advantage and disadvantage and the current progress of them are also illustrated here.2. Several methods of curve fitting are illustrated and their fitting precision and specialty are compared. Furthermore, the method of non-linear least squares fit is selected as the the practical fitting method according to the need of the research.3. The imaging error as well as its influence to the imaging quality is researched in order to find several parameters which have a closer relation with the imaging quality. The parameters are tangent vector error, the radius of curvature error and focusing error.4. The formula and flowchart of the ray tracing calculation are presented by which the intersection point of the light and the optic axis can be obtained.5. The methods above are used in practical data-processing. The errors of the tangent vector, the radius of curvature and the focusing are obtained through curve fitting and ray tracing. Finally, the charts are ploted by the matlab emulation.