Overview
ISO 14880-3:2006 - "Optics and photonics - Microlens arrays - Part 3" specifies standardized test methods for optical properties (other than wavefront aberrations) of microlenses in microlens arrays. It applies to very small lenses formed on one or more surfaces of a common substrate and to graded-index microlenses. The standard defines measurement principles, test equipment, preparation, procedures, reporting and uncertainty considerations to improve compatibility and interchangeability of microlens-array products.
Key topics and technical requirements
- Scope: Tests focus on optical properties other than wavefront aberrations (wavefront testing is covered in ISO 14880-2).
- Substrate quality: Optical substrate contribution must be quantified (referenced to ISO 10110-5).
- Primary test techniques:
- Microscope technique (main body): locate the microlens surface and determine effective back/front focal length by measuring axial displacement required to refocus on an image of a distant source.
- Interferometric methods (Annex A): Fizeau, Twyman-Green, lateral shearing and Shack‑Hartmann devices for locating surfaces or centers of curvature.
- Confocal measurement (Annex B): alternative method for effective focal length of lens arrays.
- Shack‑Hartmann technique (Annex D): parallel measurement of focal spot positions.
- Measurement elements:
- Test system: microscope with displacement transducer, suitable light source, test object (optical fibre tip or graticule), camera/monitor and image analyser.
- Microscope requirements: focusing aid (e.g., split-image), objective NA greater than microlens NA at focus, calibrated displacement measurement.
- Light sources: white light, filtered bands or lasers; report spectral properties.
- Calibration: use standard microlens artefacts and step-height artefacts to verify system performance.
- Chromatic aberration: measure focal length at specified wavelengths and characterize dispersion (Abbe number) from focal-length data.
- Environment & preparation: temperature control (preferably 20 °C), clean optical surfaces, minimize vibration, describe detector sampling and intensity linearity.
- Results/reporting: include uncertainties, test conditions and calibration traceability; Annex C discusses coupling efficiency and imaging quality.
Applications and users
ISO 14880-3 is practical for:
- Optical engineers and metrology labs performing focal length, chromatic dispersion and focal spot uniformity tests on microlens arrays.
- Manufacturers and quality‑control teams validating microlens-array components for displays, sensor coupling optics, arrayed light sources, image sensors, 3-D displays and optical parallel processors.
- R&D groups developing graded‑index microlenses and integration processes for micro‑optics.
Keywords: ISO 14880-3, microlens arrays, microlenses, test methods, focal length measurement, chromatic aberration, interferometry, Shack‑Hartmann, confocal measurement.
Related standards
Open preview (PDF)Optics and photonics — Microlens arrays — Part 3: Test methods for optical properties other than wavefront aberrations