IEC 62679-3-3:2016

Overview

IEC 62679-3-3:2016 specifies standard measurement conditions and optical measuring methods for electronic paper displays (EPDs) that incorporate an integrated lighting unit (ILU) such as a front light. The standard applies to segmented or matrix EPDs, monochromatic or colour, operated in reflective mode with the ILU turned on in dark or indoor ambient lighting. Colour systems with more than three primaries are excluded. IEC 62679-3-3 is part of the IEC 62679 family addressing EPD test methods and references CIE colourimetry systems (CIEXYZ/1931, CIE 1976 u′v′ and CIELAB).

Key topics and technical requirements

• Standard measuring conditions
  • Environmental and viewing-direction coordinate system
  • Dark-room and standard indoor ambient illumination spectra and geometries
  • Adjustment of the EPD and locations of measurement fields for matrix and segment displays
• Optical measurement methods
  • Hemispherical diffuse reflectance and reflectance factor for directed sources
  • Photometric uniformity (in dark room with ILU on)
  • Contrast ratio: dark-room and under indoor illumination
  • Cross-talk measurement for greyscale and binary matrix displays
  • Colour measurements: colour gamut, colour gamut area and gamut volume (CIELAB), and colour under indoor illumination
  • Colourimetric uniformity (in dark room) and viewing-direction dependence (angular performance)
• Measurement equipment and references
  • Standardized use of spectroradiometric/colourimetric instrumentation, tristimulus calculations, and reference illuminants (e.g., CIE daylight definitions) as described by the standard
• Record keeping and evaluation
  • Defined measurement points, evaluation metrics and reporting formats for repeatable, comparable results

Practical applications and who uses this standard

• EPD manufacturers - to verify optical performance during design, production and quality control.
• Test laboratories - for standardized measurement protocols when certifying or benchmarking EPD modules with ILUs.
• Procurement and specification authors - to write objective, measurable requirements for displays in e-readers, signage, industrial HMIs and low-power colour displays.
• R&D and system integrators - to compare front-light designs, colour performance and viewing-angle behaviour under realistic indoor lighting. Using IEC 62679-3-3 ensures repeatable, internationally comparable optical data (reflectance, contrast, colour gamut, uniformity, cross-talk) for EPDs with integrated lighting.

Related standards (if applicable)

• Other parts of the IEC 62679 series (EPD measurement standards)
• CIE colourimetric standards and illuminant definitions (CIEXYZ/1931, CIELAB, CIE 1976 u′v′)
• Relevant IEC test-method standards for display measurement and photometry

Keywords: IEC 62679-3-3, electronic paper displays, EPD, integrated lighting unit, front light, optical measuring methods, reflectance, contrast ratio, colour gamut, CIELAB, photometric uniformity, viewing-angle.