Overview
ISO/TR 9241-313:2025 - Ergonomics of human-system interaction, Part 313 - provides background and a validated methodology for optical reflection measurements of flat direct‑view electronic displays, with a focus on reflective displays such as electrophoretic displays (EPDs). The report explains how to measure and model reflection components so measured reflection coefficients can be used to predict display performance under specified indoor and outdoor ambient illumination conditions. It is a Technical Report that complements other parts of the ISO 9241 series and does not prescribe an ergonomics evaluation methodology.
Key topics
- Reflection measurement methodology for flat direct‑view electronic displays, including definitions, calibration standards and diagnostic samples.
- Measurement geometries and instruments:
- BRDF (bi‑directional reflection distribution function) measurement approaches
- Imaging sphere, conoscope, gonioreflectometer
- Variable aperture source (VAS) and annulus source techniques
- Separation and quantification of fundamental reflection components:
- Specular, haze (off‑specular), and Lambertian (diffuse) reflection
- Source‑size dependence of haze and specular components
- Methods to derive spectral radiance and predict display contrast and reflected luminance under multi‑source ambient illumination (indoor and outdoor scenarios)
- Examples and demonstrations on EPDs, with methods applicable to other reflective and some emissive displays
- Alignment with ambient illumination definitions from CIE and ISO/CIE references for indoor/outdoor conditions
Practical applications
- Display manufacturers: validate and optimize coatings, surface treatments, and optical stacks to improve readability in real-world light conditions.
- Test laboratories and quality engineers: standardized procedures to measure BRDF, specular/haze components, and predict contrast under ambient illumination.
- Product designers and systems engineers: predict product performance (sunlight readability, indoor glare) early in design and select mitigation strategies (anti‑reflective coatings, matte finishes, optical films).
- Researchers: compare reflective display technologies (EPD vs. other reflective or emissive solutions) using consistent optical metrics.
Benefits
- Enables objective, repeatable optical reflection testing for reflective displays.
- Translates measured optical characteristics into predicted visual performance in specific ambient environments.
- Supports design decisions to improve readability, reduce glare, and optimize user experience for low‑power reflective displays.
Related standards
- ISO 9241 series (ergonomics of human‑system interaction), including parts on visual performance and measurement
- Relevant CIE documents (e.g., CIE 015:2018, CIE S‑017:2020) and ISO/CIE colorimetric references cited in the report
Keywords: ISO/TR 9241-313:2025, reflective displays, optical measurement, electrophoretic displays, EPD, BRDF, variable aperture source, ambient illumination, display contrast.