Overview
IEC 62899-402-3:2021 defines a practical, optical, two‑dimensional (2D) image‑based method for detecting and characterizing voids in printed patterns used in printed electronics. The standard specifies how to acquire 2D optical images (microscope or camera), identify voids visible from a top view, and report void‑related attributes such as count, size, area and void ratio. It targets voids that are distinguishable by optical imaging and emphasizes cost‑effective quality control for manufacturing and R&D where 3D profilers are impractical.
Key topics and requirements
- Scope and definitions
- Voids are defined as imperfections visible in a 2D top‑view (pinhole/hollow types that expose absence of ink).
- Regions defined: Region of Interest (ROI), pattern area, and background area.
- Measurement environment
- Specifies standard atmosphere for evaluation and conditioning in line with ISO 291 (temperature and relative humidity classes cited).
- Measurement procedure
- Image acquisition using an optical microscope or camera.
- Preparation of specimen and ROI selection to separate pattern and background areas.
- Image processing steps to detect voids (binarization based on brightness levels).
- Void thresholding
- Use of a void threshold derived from pattern and background brightness and a void threshold index (Z) to discriminate void pixels from intact pattern pixels.
- Annex A (normative) supplies guidance on setting thresholds and examples of detection sensitivity.
- Output/attributes
- Quantified attributes include number of voids, void sizes, total void area, and ratio of void (total void area divided by pattern area).
- Annex B (normative) covers size distribution of voids.
- Reporting
- Required report items: measurement identification, instrument specifications, sampling positions, and measured results (examples provided in the standard).
- Limitations and recommendations
- Only optical 2D‑distinguishable voids are measurable.
- Cautions against misdetection on rough/thick patterns (e.g., screen‑printing); recommends complementary surface roughness measurement where appropriate.
Applications and users
- Quality control and process monitoring in printed electronics manufacturing
- Printability and ink/process development in R&D labs
- Suppliers of printing equipment and vision inspection systems
- Reliability engineers assessing defect causes in printed conductive traces, sensors, OLED/OPV layers, RFID antennas and other printed devices
- Standards developers and test laboratories implementing reproducible void‑detection procedures
Related standards
- Part of the IEC 62899 series on Printed Electronics (see IEC TC 119 work).
- Normative reference to ISO 291 for conditioning and testing atmospheres.
- Complementary standards in the series cover other printability and measurement topics (refer to IEC webstore for the complete list).
Keywords: IEC 62899-402-3:2021, printed electronics, printability, void detection, 2D optical image, void threshold, void ratio, ROI, measurement method, quality control.
Open preview (PDF)Printed electronics - Part 402-3: Printability - Measurement of qualities - Voids in printed pattern using a two-dimensional optical image
