On the description of zonal aspheric surfaces
American Journal of Optometry and Physiological Optics
|February 1, 1986
Summary
The off-set model incorrectly predicts tangential power errors in zonal lenses. Measurements show continuous errors, suggesting a co-axial model is more accurate for these aspheric surfaces.
Area of Science:
- Optics and optical engineering
- Surface metrology
Background:
- Zonal aspheric surfaces are used in optical systems.
- Previous models, like the off-set model, have been proposed to describe their properties.
- The off-set model predicts specific behaviors of sagittal and tangential power errors at zone boundaries.
Purpose of the Study:
- To evaluate the accuracy of the off-set model for zonal aspheric surfaces.
- To investigate the behavior of sagittal and tangential power errors in commercially available zonal lenses.
- To propose a more accurate model for describing zonal aspheric surfaces.
Main Methods:
- Analysis of surface equations to determine curvature dependencies.
- Review of the off-set model's predictions for power errors.
- Experimental measurements of power errors on commercial zonal lenses.
Main Results:
- Sagittal curvature depends on the first derivative; tangential curvature depends on first and second derivatives.
- The off-set model predicts continuous sagittal power errors but discontinuous tangential power errors.
- Measurements revealed continuous sagittal and tangential power errors across zone boundaries, contradicting the off-set model.
Conclusions:
- The off-set model is likely incorrect for describing zonal aspheric surfaces.
- A co-axial model is proposed as a more accurate representation.
- Understanding these surface properties is crucial for optical lens design and manufacturing.
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