Overview - IEC 62595-2-5:2021 (Display lighting unit)
IEC 62595-2-5:2021 is an international measurement standard that defines methods for measuring optical quantities of non‑planar light sources (NPLSs) - specifically convex and concave cylindrical light sources used in displays. It covers NPLSs with continuous, distinct, segmented or block‑wise radiating surfaces (examples: OLED panels, integrated LEDs, mini‑LEDs, micro‑LEDs, laser diodes), whether monochromatic or polychromatic. The standard focuses on repeatable, metrologically sound procedures for luminance, chromaticity, luminous flux and related directional/lateral characteristics.
Key technical topics and requirements
- Scope of measurements: convex and concave cylindrical geometries; measurement field (MF) definition and projection on curved surfaces.
- Measurement devices: spot‑type light measuring devices (LMD), spectroradiometers (spectral radiance meters), integrating spheres/flux meters, goniometric setups and electrical measurement instruments (current, voltage, power).
- Measurement conditions: standard environmental and darkroom conditions, warm‑up procedures, and electrical set‑up consistency for reproducible results.
- Optical measurement methods:
- Lateral scanning and directional scanning configurations for curved sources.
- Quantities: lateral luminance, lateral luminance uniformity, lateral and directional chromaticity and chromaticity variation, directional luminance and variations, luminous flux.
- Perceptual visual quality considerations and procedures.
- Metrological considerations: depth‑of‑field (DoF) and depth‑of‑focus (dof) for LMDs on curved surfaces, measurement field aperture and inclination angle, and circle of confusion impacts.
- Reporting and precautions: recommended reporting items, uncertainty awareness and measurement caveats.
- Informative annexes: projection/contour math for measurement fields on cylindrical surfaces, planar comparisons, and aperture/inclination guidance.
Practical applications and users
Who will use IEC 62595-2-5:
- Display and lighting manufacturers developing curved OLED, LED and micro‑LED modules.
- Test laboratories and calibration facilities performing optical qualification, QA and compliance testing.
- Optical engineers, metrologists and product designers validating luminance uniformity, color performance and directional emission.
- Certification bodies and R&D teams comparing curved display lighting performance across designs.
Practical benefits:
- Enables consistent, comparable measurements for curved display light sources.
- Improves accuracy in reporting luminance, chromaticity and flux for product datasheets and compliance.
- Supports product optimization (uniformity, viewing angle, colour stability) and reliable supplier / vendor comparisons.
Related standards and integration
- Part of the IEC 62595 series (Display lighting unit) and intended to be used alongside other IEC optical and photometric standards and instrument calibration guides (e.g., spectroradiometer and integrating sphere practice). Use IEC 62595‑2‑5 to complement existing photometric test methods when dealing with non‑planar light sources.