Overview
IEC 61747-40-6:2018 - "Liquid crystal display devices - Part 40-6: Mechanical testing of display cover glass for mobile devices - Retained biaxial flexural strength (abraded ring-on-ring)" specifies a mechanical performance test for display cover glass used in mobile devices. The standard defines a controlled grit particle abrasion procedure to introduce surface flaws, followed by measurement of the retained surface fracture load using the ring-on-ring (biaxial flexural) test method referenced from IEC 61747-40-4. The goal is to quantify how abrasion damage reduces fracture load and to provide repeatable comparative data for glass materials and treatments.
Key topics and requirements
- Two-step test sequence: (1) controlled particle abrasion of specimens; (2) retained failure load testing with the ring-on-ring method (IEC 61747-40-4).
- Specimen guidance: typical specimen size example is 50 × 50 mm, thickness 0.55 mm to 2.0 mm; sample size example is 30 specimens.
- Abrasion apparatus and materials: description of an abrasion device, specimen holder and grit particle media; clause-level details govern device geometry and particle containment.
- Abrasion conditions: typical abrasion pressures stated in the standard range from about 34.5 kPa to 310.3 kPa (more commonly 34.5–103.4 kPa), with rare use above 413.7 kPa; exact pressure selection depends on glass type and target damage.
- Iterative calibration: an iterative approach (e.g., 10-specimen trial) may be used to select an abrasion pressure that produces field-relevant check depths; Annex A describes check-depth measurement by fractography.
- Retained fracture measurement: specimens are tested in biaxial flexure (ring-on-ring). Load-at-fracture values are reported without normalization to classical formulas due to possible non-linearities.
- Statistics and reporting: Weibull statistics of post-abrasion fracture loads are used to report sample performance.
- Safety and handling: precautions for broken glass and airborne particulates; specimen preservation (adhesive tape over fracture surface and PTFE film on support ring) to protect surfaces and reduce fragment scattering.
- Environmental conditioning and calibration: pre-conditioning times and calibration traceability requirements referenced to IEC 61747-40-1.
Applications and users
- Quality assurance and acceptance testing for mobile device cover glass
- Material selection and comparative evaluation of glass compositions and surface treatments (e.g., ion-exchanged glass)
- R&D and failure analysis to correlate abrasion damage to retained strength
- Test laboratories and manufacturers of displays, touch covers, and glass suppliers seeking reproducible metrics for abrasion resistance and retained biaxial flexural strength
Related standards
- IEC 61747-40-1 - Guidelines for mechanical testing of display cover glass
- IEC 61747-40-4 - Biaxial flexural strength (ring-on-ring) - method used to measure retained fracture load
Keywords: IEC 61747-40-6, retained biaxial flexural strength, abraded ring-on-ring, cover glass abrasion testing, grit particle abrasion, ring-on-ring test, retained surface fracture load, mobile device display glass.
Open preview (PDF)Liquid crystal display devices - Part 40-6: Mechanical testing of display cover glass for mobile devices - Retained biaxial flexural strength (abraded ring-on-ring)
