Method for designing progressive addition lenses
First Claim
1. A method of designing the surface of a progressive addition lens having an upper portion for distance viewing, a lower portion for close-up vision, a transition zone between the upper and lower portion, and two peripheral zones, comprising the following steps:
- producing a desired pattern of grid lines in which the astigmatism is distributed over the entire pattern of grid lines in a predetermined manner,applying ray tracing to determine what lens surface is required to obtain said desired pattern of grid lines, by assuming a grid viewing system from which rays are traced, calculating surface normals for each grid crossing by using the grid object and grid image as known quantities and solving for each surface normal using the law of refraction, anddetermining the surface heights of the lens directly from said calculated surface normals for each said grid crossing.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of designing progressive addition lenses is provided in which the surface of the lens is in effect synthesized directly from its specification. A desired pattern of grid lines is produced in which the astigmatism is distributed over the entire pattern of grid lines in a predetermined manner, a standard grid viewing system from which rays are traced is then assumed, and surface normals for each grid crossing are calculated by using the grid object and grid image as known quantities and solving for each surface normal using the law of refraction and determining the surface of the lens from the respective surface normals.
109 Citations
3 Claims
-
1. A method of designing the surface of a progressive addition lens having an upper portion for distance viewing, a lower portion for close-up vision, a transition zone between the upper and lower portion, and two peripheral zones, comprising the following steps:
-
producing a desired pattern of grid lines in which the astigmatism is distributed over the entire pattern of grid lines in a predetermined manner, applying ray tracing to determine what lens surface is required to obtain said desired pattern of grid lines, by assuming a grid viewing system from which rays are traced, calculating surface normals for each grid crossing by using the grid object and grid image as known quantities and solving for each surface normal using the law of refraction, and determining the surface heights of the lens directly from said calculated surface normals for each said grid crossing. - View Dependent Claims (2, 3)
-
Specification