New Optics Drawings Standards
Jun 30, 2016
ABOUT THIS WEBINAR
Join us for a FREE webinar! Dave Aikens, the leader of the project to adopt ISO 10110 as an American National Standard, will provide an introduction of OP1.0110, the American National Standard for optics drawings.
Since the late 1990s, the optics community has gradually been converting optics drawings from a free-form, notes-based method to a standardized, international pictographic method. In 2015, the United States joined the international community by adopting a version of ISO 10110 as the American National Standard for optics drawings. This new method is a great boon for an industry in need of standardization, but can be confusing to the uninitiated.
Dave will discuss the format of the drawings, as well as an overview of the tolerance notations for things like glass parameters, surface wave front, imperfections and texture. He will also explain how OP1.0110 differs from ISO 10110 and provide insight into how both standards will change in the coming decade.
Dave Aikens is president and founder of Savvy Optics Corp., and has been involved in optics drawings and specifications for over 30 years. He is the head of the American delegation to ISO TC 172 SC1 which published ISO 10110, and is the Secretary of the American Standards Council for Optics, ASC OP, which published OP1.0110, the American National Standard for optics drawings.
Audience questions and presenter Dave Aikens’ responses are provided below:
1. For coatings does R assume R absolute or R average? Second, are there treatments for various polarizations and AOIs for coating performance?
If no polarization is indicated, the reflectivity is based on unpolarized light, per OP1.9211-2. If you are referring to a spectral range, such as from 480-640 nm, R indicates reflectivity at all wavelengths, while Rave represents the average of all wavelengths. For more information about coating types and definitions, please see OP1.9211-1 through OP1.9211-4. Their ISO equivalent are ISO 9211-1 through ISO 9211-4.
2. How would you represent lenses with a diffractive surface?
The currently published version of the standard does not apply to diffractive surfaces. The new revision of ISO 10110-1, expected in 2017, will include a new notation for “special optical surfaces” but does not provide much assistance in specifying such a surface. ISO CD 10110-16 was meant to address diffractive surfaces, but has never been completed. This will be discussed in Bucharest in October 2016 by the committee.
3. Where do you cover the coating durability, on the drawing or a separate document?
Durability of coatings is described in OP1.9211-3 and ISO 9211-3, and testing is described in OP1.9211-4. For non-standard durability requirements, the requirement is indicated in a note.
4. Should ISO10110-17 be used in place of ISO21254 for laser damage?
ISO 10110-17 is the notation standard to allow you to put a laser damage requirement on the drawing. ISO 21254 is a metrology standard, to validate a specific damage requirement via testing.
5. What is the default for a chamfer, for example 0.5mm x 45 deg. Is 0.5mm the face width or the "leg" dimension?
0.5 mm is the minimum face width.
6. How about prisms, waveplates, etc.
Prisms can be drawn using ISO 10110 by indicating surface numbers in the drawing field and then adding additional columns to the table field. Waveplates are drawn as windows with a note indicating their retardance in the drawing field. Note that the next edition of ISO 10110-1, which is expected in 2017, will include new drawing formats that assist with these types of components.
7. Regarding RMS slope: you mentioned how we can specify on the DWG, but how to measure in a way that is platform insensitive? The Zygo way of pixel to pixel gradients IS resolution sensitive (when combined with noise). We tried and our results for RMS slope differ by 40-50% from our vendors', both using Zygo on the exact same lens surface but different CCD resolutions. Guidance?
There is no guidance offered in ISO or OP at this time, but a new standard under development, OP1.005, includes information on the correct calculation of RMS slope. The best approach is to make a note on the drawing indicating that the slope is calculated on data which has been filtered with a smoothing function, such as a Chetwynd filter function. Slope calculations in ISO 4287 for texture use this as the default. (Our efforts to make this the default in ISO 10110 were not successful).
8. If one has a crystalline material doesn't the cut axis of the crystal need to be called-out?
Yes, any special optical material properties such as the crystallographic axis should be indicated on the drawing, but the standard does not offer any guidance on how this is done, or what happens when it is not indicated or toleranced.
9. I'd like to know if this standard applies to plastics as well. There is a lot of specific mention to glass. Thank you.
The ISO 10110 series applies to optical elements and systems, and does not preclude the use on plastic optics, but neither does it provide any assistance in specifying plastic materials properties. This is presumably done with a note.
10. What about gradient index materials?
The ISO 10110 series applies to optical elements and systems, and does not preclude the use on GRIN optics, but neither does it provide any assistance in specifying GRIN properties. This is presumably done with a separate document, or a note.
11. What is the best way to indicate allowed glass substitutions (or if substitutions are not allowed?)
If substitutions are allowed, I recommend using the international glass code instead of the manufacturer product label. Standard practice is to add the phrase “or equivalent”. If neither of these is used, the component must be manufactured from the indicated material without substitution.
12. Do all surface form tolerances apply after coating?
All indications apply to the finished part. Thus if the surface form is intended to apply prior to coating, there needs to be a note indicating this, or the coating needs to be on its own drawing.
13. T and R are used to specify Transmission and Reflectivity but how are the different polarizations handled, subscript?
Yes. A subscript of p and s is used for linear polarizations. More information is provided in OP1.9211-3 and ISO 9211-3.
14. Chamfers are length of legs. What is the length on bevel? What is the surface texture on the annulus?
The chamfer tolerance is on the face-width, not the legs. A bevel must be specified and toleranced completely, including indication of angle, length, etc. In the drawing in slide 14 et seq. of the presentation, there is no requirement on the surface texture of the face flat. This is an error (it should have been indicated as “G”), but the lack of any indication would imply the face flat can be ground, polished, or whatever, at the discretion of the manufacturer. There is no default.
15. How does ISO deal with defining crystal material requirements?
There is no guidance on crystal material properties or tolerances, so they must be provided in a note.