This part of ISO 25297 specifies the information requirements for optical systems and parts, and provides an

information model to support the processes of optical design, optical evaluation and analysis for these optical

systems and parts when using computers with CAD and CAE.

NOTE Generally, an optical system means an optical unit as an optical product, which performs optical functions,

and is composed of optical elements and the barrels in which these elements are mounted. In this part of ISO 25297, an

optical system is a collection of optical parts and optical assemblies, e.g. the viewfinder system or the taking lens system

of a leaf shutter camera.

This information model adds the data peculiar to optical design specification based on STEP to ISO 10303

(all parts). The additional information is product specification information, optical design information, optical

evaluation information and analysis information.

This part of ISO 25297 is generically called the Neutral Optical Data Interchange Format (NODIF).

The following are within the scope:

— information on product specification, optical design, optical evaluation and analysis;

— optical systems and parts in imaging systems, such as cameras and copiers, viewing systems for

telescopes and microscopes and the other optical systems, such as projectors and pick-up lenses;

— multiple-configuration optical systems, including zoom lenses and inner focusing systems;

— optical path definition, including ray-path sequence and optical surface arrangement;

— optical assemblies, including cemented parts and dynamic parts;

— mathematical description of the optical surface form;

— description of diffractive surfaces;

— machining process designation, such as polishing, molding or replicating;

— optical material specifications, such as material names, lot numbers and measured refractive indices;

— optical tolerances for the shape and material property of each optical part;

— assembly tolerances, such as separation, parallelism, displacement and tilt.

— effective diameters, coatings and protective surface treatment;

— paraxial evaluation, such as focal length, back focal length, principal points and f-number;

— ray-tracing evaluation, such as geometrical ray-tracing results (i.e. ray directions and intersection points

on each surface and optical path lengths), aberrations and wavefront aberration;

— OTF evaluation based on geometrical and/or physical optics;

— illuminance distribution on a detection surface or a projection surface;

— spectral characteristics;

— ghost image evaluation;

— thermal analysis accompanying optical surface deformation and material property value change;

— stress analysis accompanying optical surface deformation and material property value change;

— veiling glare and surface imperfections.

The following are outside the scope of this part of ISO 25297:

— mechanical design, electronic design and embedded software design;

— optical systems in which the optical path is changeable, e.g. beam splitters or variable magnification converters;

— tolerances for mechanical parts;

— parts with a diameter less than 10 times the wavelength of light;

— parts made from materials whose dielectric constant, σ, electric permittivity, ε, and magnetic permittivity,

μ, are uninfluenced by interaction between the materials and the light;

— graphical documents resulting from design, evaluation and analysis of products;

— optical wave guide for optical communications;

— product planning information concerning market research and customer analysis;

— product definition and configuration control information irrelevant to design, evaluation and analysis;

— analysis information, except thermal and stress analysis, e.g. vibration analysis;

— information on trial production, production process including production planning and production control,

and processes after production, such as shipment and repair;

— ophthalmic optics.