IEC 62899-402-2:2020

Overview

IEC 62899-402-2:2020 - part of the IEC 62899 printed electronics series - defines standardized methods to measure edge waviness of printed patterns used in printed electronics. The standard specifies an optical measurement workflow (image acquisition, instrument requirements, image preparation, data collection and analysis) and precise definitions of edge-related attributes-such as inner edge, test line, average edge (1σ), touch edge (2σ) and distribution edge (3σ)-based on relative gray value (RGV) distributions. It focuses on optical measurement systems and reporting; it does not standardize specific instruments.

Key topics and technical requirements

• Scope: Measurement methods for edge waviness to assess printability in printed electronics.
• Definitions: Clear terminology for inner edge, test line, ROI (region of interest), sampling length, and RGV-based edges (1σ, 2σ, 3σ).
• Atmospheric conditions: Standard atmosphere per ISO 291 - typically 23 ± 2 °C and 50 ± 10 % RH (tighter class-1 limits for plastic substrates where specified).
• Image acquisition:
  • Field of view must include a statistically significant edge length and at least five cycles of peak/valley within the sampling length.
  • Lighting must be uniform; optics must provide sufficient depth of field.
• Instrument recommendations:
  • Optical microscope with at least 20× magnification.
  • Visible light sources (halogen, LED).
  • CCD or CMOS sensors (8 megapixels or higher suggested).
• Analysis software: Must read gray values and compute RGV, produce distribution graphs correlating distance from inner edge (x axis) with RGV ratio (y axis).
• Reporting: Test identification, instrument specifications, atmospheric conditions and numerical results (average/touch/distribution edges and distribution graphs).

Applications and users

IEC 62899-402-2 is practical for:

• Printed electronics manufacturers and process engineers validating printability and edge quality of conductive ink traces, printed circuits, sensors and displays.
• Ink and substrate developers optimizing formulations to reduce edge waviness.
• Quality control and metrology labs performing reproducible optical edge measurements.
• Equipment suppliers (scanners, microscopes, imaging systems) who need to align product capabilities with standard requirements.

Practical benefits include objective, repeatable assessment of printed pattern edge amplitude, improved process control, and better comparability across suppliers and production lines.

Related standards

• ISO 291 (standard atmospheres for conditioning and testing) - referenced for environmental conditions.
• Other parts of the IEC 62899 series (Printed electronics) for broader printability and measurement guidance.

Keywords: IEC 62899-402-2:2020, printed electronics, edge waviness measurement, printability, ROI, relative gray value, optical measurement, sampling length, microscope, CCD, CMOS.