A Study of Optical Design with Genetic Algorithm for Aspherical and Free-form surfaces in Multifocal Artifical Introcular Lens

• Main Authors: Shih-Cyuan Jin, 金仕全
• Other Authors: Chih-Ta Yen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/8p4h89

碩士 === 國立虎尾科技大學 === 電機工程研究所 === 103 === The crystalline lens focus will slowly degenerate with the growth of age, and produce presbyopia, cataracts and other symptoms, so that light can not be focused on the retina, so the human to correct artificial intraocular lens(IOL) by medical research , when light enters the eye , that we can adjusted via IOL, regained focus light effect. The study is main divided into two parts, the first part is design aspheric artificial intraocular lens, that it''s can be adjusted in the state of function of use aspherical lens as the design of multifocal lens,that because aspheric have variability mirror group of more liberal in optimization process , so divided three zoom of far, middle, nearly ; the second part is design a multifocal non-adjustable type of free-form surface , mainly using a Fresnel lens (Fresnel Lens) as a crystalline lens, that without adjusting the lens to achieve a multifocal function. Due Fresnel lens is have limitations by more complicated lens group in the optimization process, so divided two zoom of far and nearly. The software is CODE V optical simulation design, that using of genetic algorithms (GA) to obtain the optimum value of the curvature, thickness, aspheric coefficients and diffraction grating, thereby to find the multifocal IOL of optimal solution, to simulate IOL corresponds far,medium, near state regulation, reducing third-order aberrations, and improve MTF. There are two different free-form surface into the pupil(5mm, 6mm), mostly in the state of analysis different pupil optimal results, when the pupil of 5mm, the simulation results in the artificial Intraocular lens all have the part of merits and inferior. In the nearly zoom of artificial Intraocular lens, GA in the Spot Diagram and MTF (spatial frequency 15cycle / mm) improvement rate averaged 10.08%, 2.86%, but in the far zoom is inferior to the CODE V respectively averaged 16.32%,10.47%; In the state of hyperopic at nearly zoom, Spot Diagram and MTF (spatial frequency 15cycle / mm) CODE V is inferior respectively average of 23.33%, 5.13%, but GA''s improvement rate is respectively average 0.1%,2.86 % in the far zoom. From the overall result seems optimize of GA and CODE V is about the same effectiveness in the pupil of 5mm SA and TAS, SAS can''t way to improve of artificial Intraocular lens in the pupil of 6mm, that the improvement rate average were inferior to CODE V optimization 0.885%, 13.59%, 4.775%, but analysts of the Spot Diagram and the MTF are have good results, that Spot Diagram can average improve of 17.27%, 11.32%. MTF (spatial frequency 15cycle / mm) can average improve of 10.78%, 10.06%. Overall optimization results which, that the aspherical of GA is to achieve improved. In the free-form surface optimization results, although optimization of the entrance pupil of 5mm as a result can''t achieve an overall improvement, but its effectiveness is with CODE V optimization similar, and in the entrance pupil of 6mm when the overall effect is have promotion, which can be learned in the overall optimization results, GA can indeed achieve the effect of improvement. Keywords：artificial Intraocular lens, Fresnel lens, aspherical lens, genetic algorithms