IEC 62679-4-2:2016

IEC 62679-4-2:2016 - Electronic paper displays (EPD) - Environmental test methods

Overview

IEC 62679-4-2:2016 defines environmental test methods to determine the environmental reliability of electronic paper displays (EPDs) - panels and modules - during storage under assumed usage conditions. The scope is limited to segment, passive and active matrix EPDs, in monochrome or colour, and is intended for devices operated in reflective mode. The standard sets out measuring conditions, recovery procedures and test methods relevant to storage, temperature, humidity, pressure and light exposure.

Key topics and requirements

• Measuring and reference conditions
  • Standard measuring environmental conditions and atmospheric reference conditions for repeatable measurements.
  • Defined recovery conditions and procedures to assess reversible/irreversible effects after stress.
• Environmental storage tests
  • High temperature and low temperature storage tests to verify long‑term stability in extremes.
  • Temperature shock tests (two‑chamber) and specified temperature change rate tests (one‑chamber) to assess robustness to rapid thermal transitions.
• Temperature/humidity tests
  • Combination temperature/humidity test and temperature/humidity cycling to simulate real-world moisture and thermal cycling.
• Low air pressure
  • Low pressure (altitude) test method for storage when evacuated or transported at reduced pressure.
• Light exposure and solar simulation
  • Procedures for light exposure including direct sunlight, daylight through window glass and inner part exposures.
  • Guidance on solar spectral irradiance, use of xenon‑arc lamps and calibration against CIE solar spectra.
• Reporting
  • Required information to include in specifications and test reports for traceability and comparability.

Practical applications - who uses this standard

• EPD manufacturers - to validate storage robustness, material choices and module assembly.
• Test laboratories and qualification teams - to execute standardized environmental and light exposure tests.
• OEMs and integrators - to specify storage and transport requirements for e‑readers, signage and low‑power reflective displays.
• Procurement, reliability and warranty engineers - to set acceptance criteria and reduce field failures related to environmental stress.

Related standards and references

• IEC 62679-1-1 (Terminology)
• IEC 62679-3-1 (Optical measuring methods)
• IEC 60068-1 and IEC 60068-2-38 (environmental testing general guidance and composite temp/humidity cyclic tests)
• CIE 085-1989 (Solar spectral irradiance) - used for light exposure references

Using IEC 62679-4-2 ensures consistent, repeatable environmental qualification of reflective EPDs, improving product reliability, field performance and supply‑chain confidence.