| TOLERANCING |
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| ZEMAX supports a comprehensive, flexible, and powerful integrated tolerance analysis capability. |
ZEMAX supports a comprehensive, flexible, and powerful integrated tolerance analysis capability. Tolerances are set using a combination of user selectable options. Default tolerances include ranges on radius, fringes, thickness, position, x and y tilt, x and y decenter, irregularity, wedge, glass index, Abbe number, and more. |
Additional tolerances may be defined, including aspheric constants, decenters/tilts, solve and parameter tolerances, and others. Compensators are defined, including focus, tilt, or position of any optical element, surface, or element group. Any number of user defined tolerances is allowed. |
A tolerance criteria is then selected. ZEMAX supports RMS spot radius, RMS wavefront error, MTF, boresight error, or a completely user defined criteria. |
For more complex tolerance analysis, a user defined script may be defined which describes a step-by-step procedure used to align, adjust, and evaluate the lens. The script may change compensators and evaluation criteria during the simulated alignment and compensation process. |
Finally, ZEMAX conducts an analysis of the tolerances using any or all of these three tools: |
Sensitivity Analysis |
| The sensitivity analysis considers each defined tolerance independently. Parameters are adjusted to the limits of the tolerance range, and then the optimum value of each compensator is determined. A table is generated listing the contribution of each tolerance to the performance loss. |
Inverse Sensitivity Analysis |
| The inverse sensitivity analysis iteratively computes the tolerance limits on each parameter when the maximum or incremental degradation in performance is defined. Limits may be overall or specific to each field or configuration. |
Monte Carlo Analysis |
| The Monte Carlo analysis is extremely powerful and useful because all tolerances are considered at once. Random systems are generated using the defined tolerances. Every parameter is randomly perturbed using appropriate statistical models, all compensators are adjusted, and then entire system is evaluated with all defects considered. User defined statistics based upon actual fabrication data is supported. ZEMAX can quickly simulate the fabrication of a huge number of lenses and reports statistics on simulated manufacturing yields. |
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