IEC 62595-1-2:2016 PDF

Overview

IEC 62595-1-2:2016 - Display lighting unit - Part 1‑2: Terminology and letter symbols - is an international standard that defines preferred terms, definitions and letter symbols for display lighting units (DLUs). It covers units such as backlight units (BLUs) for transmissive and transflective LCDs and frontlight units (FLUs) for reflective LCDs and electronic paper (E‑paper) displays. The aim is consistent, harmonized terminology and quantity symbols across publications, manufacturers and test reports worldwide.

This second edition updates the series to include frontlight units, adds new terms for recent DLU technologies, corrects and aligns definitions with IEC 62595‑2 and IEC 60050, reorganizes clause structure, and improves illustrative figures in Annex A.

Key topics

• Scope and classification of terms for DLUs (fundamental, passive optical components, solid‑state light sources, frontlight‑specific, performance/specifications, backlight dimming).
• Fundamental definitions: display lighting unit (DLU), backlight unit (BLU), frontlight unit (FLU).
• BLU architectures: edge‑lit (light‑guide plate), direct‑lit (light chamber), side‑driven, single‑side/double‑side emission.
• Dynamic and directional concepts: dynamic BLUs, scanning BLUs, directional (D‑BLU) and multi‑directional DLUs, spatio‑temporal switching and field‑alternate backlights.
• Solid‑state light source terminology: LED, LED light bar and related terms used in DLUs.
• Performance and specification terms: luminance uniformity, angular luminance distribution, spectral power distribution, dimming and block/segment definitions.
• Letter symbols and units: standardized quantity and unit symbols are listed (Table 1) to ensure consistent reporting.

Illustrative figures and examples are provided in Annex A to clarify BLU/FLU layouts, angular measurements and test patterns.

Applications and users

This standard is practical for:

• Display manufacturers (LCD, E‑paper) and BLU/FLU component suppliers for product documentation and design communication.
• Test laboratories and certification bodies for consistent test reports and measurement reporting.
• System integrators and OEMs specifying display lighting requirements in procurement and contracts.
• Standards developers, technical authors and regulatory agencies seeking harmonized terminology for international publications.

Use cases include writing datasheets, test procedures, interoperability specifications, regulatory submissions and international technical documentation.

Related standards

• IEC 62595 series (other parts, notably IEC 62595‑2) - for additional requirements and consistency across parts.
• IEC 60050‑845 (International Electrotechnical Vocabulary - Lighting) - normative reference for related lighting vocabulary.

Keywords: IEC 62595‑1‑2, display lighting unit, backlight unit, frontlight unit, BLU, FLU, DLU, terminology, letter symbols, LED, LCD, E‑paper.