Overview
ISO/TR 14999-3:2005 is an ISO Technical Report on interferometric measurement of optical elements and systems, focused on the calibration and validation of interferometric test equipment and measurements. It addresses how to identify and control sources of error, quantify measurement uncertainty, and develop test procedures capable of achieving absolute or quasi-absolute calibration. This part of the ISO 14999 series complements ISO 10110 by providing practical guidance for wavefront and surface-form verification using interferometry.
Key topics and requirements
- Systematic investigation of errors: guidance for evaluating the test setup, equipment and environment to identify uncertainty sources and quantify their contributions.
- Measurement uncertainty (Type A and B): recommends combining statistical (Type A) and judgment-based (Type B) components to produce a single uncertainty statement.
- Separation of errors: procedures and apparatus to separate rotationally symmetric (e.g., spherical aberration, astigmatism-free terms) and non-rotationally symmetric error components in interferometric data.
- Dependence on physical reference surfaces: treatment of testing that relies on reference artifacts (planes, spheres, aspheres), including homogeneity testing and evaluation of reference quality.
- Absolute and quasi-absolute tests: development of optical test procedures to measure the wavefront/surface error with respect to a perfect shape rather than a bodily reference.
- Specific calibration procedures: methodologies for calibrating flats, spherical and cylindrical surfaces, windows in transmission, and testing optical systems in transmission.
- Best practices: recommendations on specifying measurands, documenting procedures, and using interlaboratory comparisons or cross-checks to detect unrecognized systematic effects.
Practical applications and users
Who benefits from ISO/TR 14999-3:
- Optical metrology and calibration laboratories validating interferometers and test rigs.
- Optical manufacturers verifying surface form and wavefront quality for lenses, mirrors, flats, aspheres and windows.
- Research and university optics labs developing high-precision interferometric tests.
- System integrators and quality managers needing documented procedures for traceable calibration, error budgeting and acceptance testing.
Typical uses:
- Establishing uncertainty budgets for interferometric measurements.
- Designing validation procedures for new test setups or reference artifacts.
- Performing absolute calibration for high-precision optical components and assemblies.
Related standards
- ISO 14999 series (Parts 1, 2, 3, 4) - Interferometric measurement of optical elements and systems.
- ISO 10110 - Preparation of drawings for optical elements and systems (surface form and wavefront tolerances).
Keywords: interferometric measurement, calibration, validation, optical elements, wavefront error, measurement uncertainty, reference surface, absolute calibration.