ISO 14880-2:2024

Overview

ISO 14880-2:2024 - Optics and photonics: Microlens arrays - Part 2: Test methods for wavefront aberrations specifies standardized methods to measure wavefront aberrations of microlenses inside microlens arrays. It applies to very small lenses formed on or within a common substrate and defines apparatus, measurement arrangements, test principles, procedure, evaluation, uncertainty estimation and reporting requirements for wavefront testing.

Key topics and technical requirements

• Test principle: Wavefront aberrations are measured using interferometers or wavefront sensors; detector planes must be conjugate with the microlens pupil and an aperture limits the measured area. Single-pass transmitted configurations are preferred to reduce spurious fringes.
• Apparatus components: Standard optical radiation source (rms aberration ≤ λ/20 over the effective aperture), collimator (NA > sample NA; wavefront aberrations recommended < λ/20), reference/standard lens (aberrations ≤ λ/20 or an order of magnitude smaller), beam‑reduction optics, aperture stops, imaging optics and image sensor.
• Measurement arrangements: Methods for single microlenses and whole-array tests are described. Choice of method depends on required measurement uncertainty, properties to measure, flexibility, cost, and whether a spot test or full-array measurement is needed.
• Interferometer and sensor methods (Annexes):
  • Annex B: Mach–Zehnder methods (Microlens test Methods 1 & 2)
  • Annex C: Lateral shearing interferometer methods (Methods 3 & 4)
  • Annex D: Shack–Hartmann sensor method (Method 5)
  • Annex E: Twyman–Green interferometer for array testing (Array Method 1)
  • Annex F: Uniformity measurement of arrays (Array Method 2)
• Performance and uncertainty: Guidance on measurement uncertainty, alignment, preparation, evaluation and required content for the test report is provided. Maréchal and Strehl criteria (≈λ/14) are referenced for collimator wavefront quality; λ/20 is recommended for several components.

Practical applications

• Ensures consistent quality control and acceptance testing for microlens arrays used in:
  • 3D displays and imaging systems
  • Coupling optics for LED/laser arrays and detectors
  • Enhanced optics for LCDs and imaging sensors
  • Optical parallel processors and micro-optical assemblies
• Useful for production testing, incoming inspection, R&D characterization and process development where wavefront quality directly affects optical performance.

Who should use this standard

• Optical engineers, metrology labs, microlens array manufacturers, quality assurance teams, and researchers in optics and photonics who require reproducible, standardized methods to quantify microlens wavefront aberrations.

Related standards

• ISO 14880-1 (Vocabulary)
• ISO 14880-3, ISO 14880-4 (other microlens characteristics)
• ISO/TR 14880-5 (selection guidance)
• ISO/TR 14999-2, ISO 14999-4 and ISO 12005 (measurement and polarization references)

Keywords: ISO 14880-2:2024, microlens arrays, wavefront aberrations, interferometer, Shack‑Hartmann, Mach‑Zehnder, lateral shearing, Twyman‑Green, optics and photonics, test methods.