Overview
EN ISO 25178-602:2025 - part of the ISO 25178 series on Geometrical Product Specifications (GPS) - defines the design and metrological characteristics of non-contact confocal chromatic probe instruments used for measuring areal surface texture. Published by CEN and corresponding to ISO 25178-602:2025, this standard covers instruments that use axial chromatic aberration of white light (confocal chromatic probes) to capture areal surface topography and supports extraction of profiles from areal data.
Key topics and requirements
- Instrument scope and configuration
- Defines the core elements of a confocal chromatic system: optoelectronic controller, fibre-optic link, and chromatic objective (optical pen).
- Notes that implementations can be point, line or field sensors.
- Metrological characteristics
- Specifies the metrological parameters and performance features required for reliable areal topography measurement (see also ISO 25178-600 for additional metrological characteristics).
- Terms and definitions
- Standardizes vocabulary (e.g., chromatic aberration, chromatic objective, confocal chromatic probe, light source pinhole, discrimination pinhole).
- Design features and instrument requirements
- Clause structure includes instrument requirements (Clause 4), metrological characteristics (Clause 5), and design features (Clause 6), plus general information (Clause 7).
- Informative annexes
- Annex A: principles of confocal chromatic profilometry for areal measurement.
- Annex B: sources of measurement error for confocal chromatic probe instruments.
- Annex C: relationship to the GPS matrix model and other GPS standards.
Practical applications and who uses this standard
- Surface metrology labs and calibration laboratories use the standard to specify, evaluate and validate non-contact optical profilers.
- Manufacturers of optical profilers and sensor developers apply the design and metrological requirements when engineering confocal chromatic instruments.
- Quality engineers, R&D teams and production metrologists use the guidance for process control, surface characterization and acceptance testing where precise areal texture or extracted profiles are required.
- Relevant for industries such as precision engineering, automotive, aerospace, medical devices and optics where surface topography affects performance.
Related standards
- ISO 25178-600: Metrological characteristics for areal topography measuring methods (referenced for additional performance criteria)
- ISO 14638 and ISO 8015: GPS framework and decision rules (contextual relations described in Annex C)
Keywords: EN ISO 25178-602:2025, confocal chromatic probe, areal surface texture, non-contact instruments, surface topography, confocal chromatic profilometry, chromatic objective, ISO 25178 series.