Overview
IEC 62595-2-1:2016 - published by the International Electrotechnical Commission (IEC) - defines electro-optical measuring methods for LED backlight units (BLUs) used in liquid crystal displays (LCDs). This first edition (2016) updates and replaces the earlier IEC 62595-2 (2012) and establishes standard measurement conditions, warm‑up procedures and test setups to determine electrical and optical parameters of LED BLUs and frontlight units.
Key Topics
- Scope and measurement conditions
- Standard atmospheric conditions: 25 °C ± 3 °C, relative humidity 25–85 %, pressure 86–106 kPa.
- Required warm‑up time until luminance and chromaticity stabilize.
- Measuring setup
- Typical test arrangement includes BLU, luminance meter (LMD), power supply, voltmeters, ammeters and block controllers for block‑wise BLUs (see Figure examples in the standard).
- Electrical measurements
- Input current, voltage and power consumption measurement methods; for block‑wise BLUs include control‑signal power.
- Optical measurements
- Luminance and luminance uniformity/non‑uniformity.
- Spectral power distribution and chromaticity measurements.
- Colour uniformity, angular luminance and angular colour uniformity.
- Defined measurement geometry using zenith (θ) and azimuth (ϕ) angles and recommended field‑of‑view and FOV considerations.
- Block‑wise BLU procedures
- Detailed measurement procedures for BLUs segmented into blocks (checkerboard, single block white/black patterns, point spread function considerations).
- Revisions vs previous edition
- Series title changed to include frontlight units; added block‑wise BLU procedures; revised key figures; editorial updates.
Applications / Who Uses It
- Display manufacturers and module integrators for validating BLU performance and producing consistent datasheets.
- Test laboratories and quality control teams for routine verification of luminance, colour and power characteristics.
- Optical and electrical engineers in R&D to compare designs and optimize uniformity, spectral output and thermal stabilization.
- Procurement and supplier QA for conformance testing in commercial agreements and acceptance criteria.
- Regulatory and certification bodies assessing measurement reproducibility for display lighting claims.
Practical Value
Applying IEC 62595-2-1:2016 ensures repeatable, comparable BLU measurement results - reducing ambiguity in luminance, chromaticity and power specifications, supporting product development, quality assurance, and supplier communication.
Related Standards
- IEC 61747-30-1 - measuring methods for LCD modules (transmissive type).
- IEC 62595-1-2 - Display lighting unit: terminology and letter symbols.
- Other parts of the IEC 62595 series - for broader display lighting unit requirements.
Keywords: IEC 62595-2-1:2016, LED backlight unit, BLU measurement, electro‑optical measuring methods, luminance, chromaticity, power consumption, block‑wise BLU, display lighting unit.