Overview
IEC 62595-2-4:2020 - “Display lighting unit – Part 2‑4: Electro‑optical measuring methods of laser module” specifies standardized electro‑optical measurement methods for laser modules used in display and display‑lighting applications. The standard covers photometric and colorimetric measurements across the visible wavelength range (380 nm to 780 nm) for modules containing multiple laser devices (edge‑emitting LDs, VCSELs, photon up‑conversion devices including SHG). It applies to modules with optical outputs such as optical fibres, waveguides, light‑guides, lens units or combined optics that deliver a combined laser beam.
Key topics and requirements
- Standard measuring conditions - environmental, dark‑room, device under test (DUT) and laser module definitions to ensure repeatable measurements.
- Safety requirements - guidance to address laser safety during measurement.
- Photometric and colorimetric tests - spectral measurements, chromaticity and centroid wavelength evaluation for narrow‑linewidth laser emissions.
- Electrical/optical characteristics - current vs. optical output (I–P) curves including CW and PWM operation, threshold current measurement and procedures.
- Far‑field pattern (FFP) - monochromatic and colorimetric FFP measurement methods for beam and illumination pattern characterization.
- Speckle measurement - monochromatic and colour speckle analysis and conversion methods to standardized, speckle‑free representations.
- Temperature dependence - procedures to characterize power and wavelength shifts with temperature for high‑ and low‑power modules.
- High‑speed modulation - pulse waveform and eye‑diagram measurement methods for fast‑modulated display lasers.
- Informative annexes - device structures (LD, VCSEL, SHG), module configurations (monochrome & RGB), wavelength/linewidth effects on chromaticity, fibre NA, coordinate conversions and measurement examples.
Applications and users
This standard is practical for:
- Display and projector manufacturers specifying and validating laser light engines.
- Optical component and laser module manufacturers for product characterization and compliance.
- Test laboratories performing repeatable photometric/colorimetric and speckle measurements.
- Lighting designers and integrators ensuring color accuracy and uniformity in display lighting systems.
- Standards and safety engineers aligning measurement methods with regulatory and quality requirements.
IEC 62595-2-4 helps ensure consistent specification, measurement and communication of laser module performance in display applications - enabling interoperability, reliable colorimetry, and safer test procedures.
Related standards
- Other parts of the IEC 62595 series (display lighting unit family) for broader system requirements.
- Relevant laser safety and photometric standards such as IEC 60825 (laser safety) and international photometry/colorimetry references.