| 摘要 |
A method and system for producing progressive addition spectacle lenses required rotating a lens blank (10) about a first axis (Z). A cutting tool (12) is reciprocated along a second axis (Z') parallel to the first axis, and is also moved along a third axis (X) orthogonal to the first and second axes. All these motions are controlled such that the cutting tool is brought into contact with the blank and reciprocated in synchronization with the rotation of the blank, thereby enabling a desired non-rotationally symmetric surface to be generated. The necessary rotary and linear motions are suitably provided by respective actuators (36, 18, 24, 30), and corresponding encoders (38, 20, 26, 32) are used to provide velocity and position information for each actuator. A processor (42) receives the encoder outputs and is arranged to provide closed loop control of each actuator. A desired surface may be provided to the processor in the form of a points file which describes the surface with an array of points having three-dimensional coordinates. The points are first converted into polar coordinates (50), then translated into motion equations which are evaluated to generate the motions necessary to create the desired surface. |
