Fig. 1. Calculation process of direct method for progressive addition lenses. (a) Meridional power distribution; (b) design results of meridional power distribution obtained by extending along contour lines on both sides of entire lens surface; (c) contour line distribution of entire surface; (d) vector height on entire surface

Fig. 2. Channel width of progressive addition lens

Fig. 3. Variations in meridional power and curvature. (a) Meridional power designed by three types of functions; (b) absolute value P'(x) of meridional power curvature

Fig. 4. Diagrams of changes in three-dimensional surface shape of optical power and projected astigmatism surface shape. (a) Graph of change in power surface shape after widening corridor; (b) graph of change in astigmatism

Fig. 5. Graphs of linear superposition of power and curvature change. (a) Graph of linear superposition of power of two functions; (b) graph of change in power curvature after superposition of functions

Fig. 6. Simulation results based on CDF. (a) Power; (b) astigmatism

Fig. 7. Simulation diagrams of lens with widened channel. (a) Power; (b) astigmatism

Fig. 8. Simulation diagrams of overlaying new function lens. (a) Power; (b) astigmatism

Fig. 9. Physical pictures of three lenses

Fig. 10. Actual measurement diagrams of lens 1. (a) Power; (b) astigmatism

Fig. 11. Actual measurement diagrams of lens 2. (a) Power; (b) astigmatism

Fig. 12. Actual measurement diagrams of lens 3. (a) Power; (b) astigmatism