ISO 10110-8:2019

Overview

ISO 10110-8:2019 - "Optics and photonics - Preparation of drawings for optical elements and systems - Part 8: Surface texture" defines how to indicate and specify the surface texture of optical elements on engineering drawings. It is intended primarily for polished optics and standardizes the representation of surface roughness and waviness using statistical and spectral descriptors. The standard prescribes a method to characterize the residual surface after detrending (subtracting the surface form), and it deliberately excludes control of surface form (handled by other ISO 10110 parts).

Key topics and technical requirements

• Scope and intent: Rules for drawing indications of surface texture for optical elements; focuses on statistical description of texture (high and mid-spatial frequency errors).
• Terminology and definitions: Clear definitions for terms such as surface texture, matt surface, optically smooth surface, detrending, residual surface, spatial wavelength and spatial band.
• Characterization methods:
  • Profile and areal metrics: rms roughness and rms waviness (profile) and corresponding areal metrics (Sa, Sq, SΔq).
  • Polish grades: Guidance for indicating polish grade for optically smooth surfaces (updated to use rms roughness values rather than micro-defect counts).
  • Spectral descriptors: Power Spectral Density (PSD) and Area Power Spectral Density (APSD) functions for frequency-domain specification of surface texture.
  • Slope metrics: Rms slope and area rms slope for assessing local surface inclination.
  • Lay and location: How to indicate texture lay and the spatial location of texture requirements on drawings.
• Measurement pre-processing: Detrending rules - the standard describes removing surface form (e.g., polynomial fit) before computing texture metrics to avoid spectral leakage.
• Drawing notation: Standardized symbols and examples for indicating matt vs. optically smooth textures and for specifying quantitative limits (annexes provide examples).
• Informative annexes: Relationship between surface texture and optical scattering; practical drawing examples.

Practical applications and users

ISO 10110-8 is used by:

• Optical designers and systems engineers specifying imaging and scattering performance
• Manufacturers and process engineers setting polishing and surface finishing targets
• Metrology labs and quality engineers creating measurement plans and acceptance criteria
• Draftspersons and CAD specialists preparing standardized optical drawings
• Procurement/specification writers ensuring clear, unambiguous contracts

Typical applications include specifying surface finish for lenses, mirrors, molded optics and precision windows where scattering, throughput and stray light depend on surface texture.

Related standards

• ISO 10110 series (general drawing rules) - see ISO 10110-1
• Surface form control: ISO 10110-5, ISO 10110-12, ISO 10110-19
• Surface texture and profile methods: ISO 4287
• Drawing indication of surface texture: ISO 1302

Keywords: ISO 10110-8, surface texture, optics and photonics, drawing indications, roughness, waviness, PSD, APSD, rms roughness, polish grade, detrending, polished optics.