Study On Evaluation Method Of Freeform Spectacle Lenses

Freeform spectacle lenses are promoted by ophthalmic optics and advanced manufacturing. It is turning with freeform technology by customization process. Modern freeform spectacle lenses are emphasized on personalized, diversified and comfortable aspects,which is different from each other. However there are no standards for freeform spectacle lenses. The measurement instruments for ordinary spectacle lenses can not be suitable for the freeform spectacle lenses measurement. The wearer can not distinguish different freeform spectacle lenses because of the coexist of the high-end market and the low market.This thesis studies on the evaluation methods and measurements of freeform spectacle lenses. The main research object is the progressive addition lens base on freeform technology.The studies in this thesis can be summarized as follows:(1)The mathematical expression of the progressive addition lens base on freeform technology is studied, the lens power distribution progressive addition lens base on freeform technology is analysed, and the distribution of the spherical and the cylinder refractive power is obtained by fitting calculation of the radial basis function. Combining with the measurement methods of the refractive parameters of progressive addition lens base on freeform technology, the refractive parameters with FFV are measured which is based on the principle of Moire technology;(2)The eye model is set up according to the optical properties of the physiological parameters of the human eye, the optical system of emmetropia, myopia, hyperopia, and hyperopia eye with corrective lens is analysed, optimized corrective lens and aspheric corrective lens. The freeform spectacle lens optical system working with the distance, the progressive corridor and the near is simulated;(3)The influence of the face fitting angle and the pantoscopic tilt to the spectacle lens to the eye systemis analysed,and the MTF varing with the face fitting angle and the pantoscopic tilt at the fixed spatial frequency and the field is discussed. Both the ordinary spectacle lens and the progressive addition lens base on freeform technology working with the distance, the progressive corridor and the near are simulated;(4)Measurement of the wavefront aberrations of the different zones on the same lens and the same zones on different lens based on the principle of the Shack-Hartmann wavefront technology are studied, and the influence of wavefront aberrations with the lens design is analysed;(5)The distortion caused by the varies of the basic lens power and additional lens power are studied, the varies trends of the distortion with the increases of the lens power is analysed, and the distortion can used to evaluate freeform spectacle lenses.