Tolerance Analysis Of Progressive Addition Lenses Surface

Progressive addition lenses(PAL)is a kind of lenses which has a very widely range of application on the modern market,The unique progressive surface can make a lens has a progressive refractive power.It can meet the human eye's different needs for distance-vision and near-vision.Firstly,The structure and efficacy of progressive addition lenses was introduced briefly in this paper.Next,Its main design methods and performance evaluation methods was elaborated.On this basis,According to the national standard that the difference between actual diopter and theoretical value should be less than 0.1D during the lens effective area,A model formula for the change of diopter and vector height was built.And using this formula to analyze a progressive addition lens which addition power is 2.09 D,The analysis result shows that tolerance value should be less than 6?m at the most sensitive area of lens surface.In addition,Several general lens aim for the presbyopic and control of juvenile myopia were designed,evaluated and analyzed tolerance in this article,which provide theoretical basis for the lens processing control precision.Finally,According to the result of the tolerance analysis,The single-point diamond ultra-precision machining equipment was used to fabricate the designed lens,And confirm the accuracy of tolerance.The tolerance analysis of progressive addition lenses solves the problem of controlling the precision of progressive surface machining,Which provides a theoretical basis for the tolerance of complex face in machining.