IEC 61747-1-2:2014

Overview - IEC 61747-1-2:2014 (Liquid crystal display devices - Terminology and letter symbols)

IEC 61747-1-2:2014 is the IEC international standard that defines the preferred terminology, definitions and letter symbols for liquid crystal display (LCD) devices. Its purpose is to harmonize language used in specifications, publications and technical documents across countries and organizations. This first edition (2014) revises the earlier IEC 61747-1 (1998 + Amendment 1:2003) by splitting the generic specification into separate parts and updating or adding terms and definitions.

Keywords: IEC 61747-1-2:2014, liquid crystal display, LCD terminology, letter symbols, IEC standard, TFT-LCD, STN, FSTN.

Key topics covered

• Preferred terms and definitions for LCD-related physical concepts (e.g., alignment layer, director, cell gap, twist angle, chiral pitch, clearing point).
• General and device-specific terms (e.g., active area, active matrix display, TFT-LCD, TN, STN, FSTN, ferroelectric and anti‑ferroelectric liquid crystals).
• Terms related to specifications and performance such as voltage holding ratio, storage capacitor, storage effect, response times and image-quality descriptors.
• Extra components and materials (e.g., electrode layer, spacers, alignment layers, compensation films, dyes for guest-host effects).
• Units and letter symbols (referencing IEC 60027, IEC 60050 and ISO 80000-1) with a dedicated table of letter symbols and illustrative figures (supply-voltage block diagram, timing-chart for response times).
• Normative references and bibliography to ensure consistent cross-referencing with other IEC and ISO vocabulary and diagram standards.

Practical applications - who uses this standard

• Display engineers and designers: to write consistent specifications and communicate device characteristics (TFT-LCD, TN, STN, FSTN, ferroelectric LC).
• Test and quality engineers: to standardize measurement terms and interpret test reports (voltage holding ratio, response time).
• Technical writers and standards committees: for clear, internationally harmonized terminology in datasheets, manuals and standards development.
• Manufacturers and purchasing/procurement teams: to avoid ambiguity in contractual specifications and component descriptions.
• Academia and translators/localizers: for accurate use of industry vocabulary and multilingual standardization.

Related standards

• IEC 61747-1-1 - Liquid crystal display devices - Part 1-1: Generic - Generic specification (split from the former IEC 61747-1).
• Normative vocabularies referenced: IEC 60027, IEC 60050, IEC 60617, ISO 80000-1.

Use IEC 61747-1-2:2014 when you need authoritative, internationally harmonized LCD terminology and letter symbols for technical documentation, product specifications, testing and cross-border collaboration.