IEC 61747-20-2:2015

Overview

IEC 61747-20-2:2015 - Liquid crystal display devices: Part 20-2: Visual inspection – Monochrome matrix liquid crystal display modules - defines quality assessment procedures and general rules for visual inspection of monochrome matrix LCD modules (excluding active-matrix types). This first edition (2015) replaces Clause 5 of IEC 61747-5:1998 and aligns document numbering with the IEC 61747 series. The standard covers inspection of both active and non-active areas, defect definitions, and human-eye (and optical microscope where necessary) inspection methods. It also notes that specific defect limits are set in the customer’s detail/quality contract.

Key topics

• Scope and purpose: Guidance for subjective visual evaluation of image defects on monochrome matrix LCD modules.
• Inspection conditions: Prescribed ambient parameters including temperature, humidity, illuminance, viewing distance and direction, and required warm‑up of the device under test (DUT).
• Inspection equipment & setup: Use of rotatable fixtures or moving inspectors, DC power, pattern generators, and optional microscope for fine defects.
• Inspector requirements: Inspectors must have normal (or corrected) vision, normal color vision, and be periodically trained using limit samples.
• Defect definitions: Classification and examples of defects such as spots, bubbles, foreign particles, stains, scratches, visible electrode structure, non‑uniform luminance, missing/unwanted picture elements, mis‑shaped picture elements, notched edges, seal edge intrusions, and pin‑holes.
• Inspection procedures & records: How to perform inspections, record results, and reference detail specifications or reference samples for rejection criteria.
• Activated vs not-activated display checks: Different test patterns and acceptance criteria apply when the display is powered (activated) versus not activated.

Applications

• Manufacturers of monochrome matrix LCD modules for instrumentation, industrial displays, consumer electronics, and appliances use this standard to define incoming inspection and production quality checks.
• Quality assurance engineers and inspection technicians apply the procedures to create consistent acceptance criteria and sampling practices.
• Procurement and contract managers reference IEC 61747-20-2 when specifying customer acceptance specifications and incoming inspection agreements with panel suppliers.

Related standards

• IEC 61747-1-2:2014 - Terminology and letter symbols for LCD devices.
• IEC 61747-10-2:2014 - Environmental, endurance and mechanical test methods (environmental/endurance).
• Other parts of the IEC 61747 series for broader display-device testing and measurement.

Keywords: IEC 61747-20-2, visual inspection, monochrome matrix LCD, liquid crystal display, defect definitions, inspection criteria, viewing area, picture elements, quality assessment.