[LPDS Draft 0.88 Review]

23 hours ago, Steve Shanbaum said:

Please find attached the 0.88 draft version of the Lens Product Description Standard.  The flexible nature of this standard will allow for a single catalog format that both lens blank manufacturers and freeform lens designers are able to use.  In the not-too-distant future, it can also serve as a catalog for optical laboratories to describe their lens offering, though that's not the focus of this initial release.

Due to the flexibility of the standard, I'm going to add a little expository text here that will hopefully help describe the very high-level usage of the standard.  Capitalized words indicate their related objects within the standard.  

When a blank manufacturer provides a new catalog, they will be including a number of Blanks, which share common features (to reduce duplication) that are grouped by a Blank Collection.  It's at the Blank Collection level that characteristics that are common across a large selection of Blanks are stored, such as a shared Material and Design.  These Blank Collections are referenced by a Product.  Though it may appear that the Product represents needless duplication of the Blank Collection, it enables the use of the standard by lens designers as well. 

Lens designers will be able to describe a Product, referencing a particular Design that can be applied to a range of Materials, without having to specify the actual Blanks to which the Design can be applied.  The consumer of the Standard will be able to know the specifications of that Design, and to which range of lenses it can be applied.  Looking down the road, this is the same flexibility that will allow the Standard to be used by a lab to electronically provide a catalog to a retailer, in that the lab can use the Standard to define a set of Products that are orderable, along with the relevant constraints on those products, such as the inclusion or exclusion of particular treatments.  

This does mean that the way the Standard will be parsed may differ depending on the consumer.  An optical lab that is importing technical specifications for a new set of lens blanks will focus on starting from the included Blank Collections.  A retailer will be more concerned with what can be ordered from the Product side, and will start the import there.  

As this is still a draft version, we are looking forward to your feedback on improving the Standard's usability and coverage.  Please feel free to comment here with your thoughts after giving the standard a read.  

As an aside, I would like to thank all the members of the editorial committee over the years (and those who might not be officially on it, but have sure spent time in the meetings at some point).  It's truly been a team effort to bring this document to the level that it's at, and I appreciate your time hashing through the topics at our numerous meetings and creating samples and diagrams.  
My many thanks to:
Adrian Blackburn
Ron Carey
Chris Eustace
Marcos Garcia
Brent Jacobs
Tony LeBlanc
Steve Nedomansky
Sebastien Piraube
Mike Vitale
Paul Wade

TVC Lens Product Description Standard 0.88.pdf 1.99 MB · 1 download

Thank you, Steven, for your hard work and leadership on this project to develop the LPDS!

[Layouts Nodes]

On 12/30/2019 at 2:13 AM, Haim Shlomo [Shamir] said:

Dear Colleagues,

Can someone explain what is the meaning of the 3 numbers under ERNRIN/UP described in the LPDS V0.78 example for layouts (p. 30)?

What are they describing?

Thanks,

Haim S.

Hi Haim,

Those 3 numbers define the range of possible values for a variable reference point. The first number is the minimum, the second is the increments, and the third is the maximum. In your example for "ERNRUP": "-8:-2:-12", it means that the possible values for ERNRUP are -8, -10, and -12.

Regards

 

 

[INSIPD and INSNPD]

On 8/10/2019 at 8:35 PM, tonyleblanc said:

I agree, there does not seem to be any existing labels which return the location of the distance MRP for all designs.  Should we also have labels which define the location of the distance MRP relative to the center of the blank, for use by analyzers which check the lens before mounting?

I am not sure if there is any lens analyzer that can verify the position of the MRP (fitting cross) from the blank center. For sure there are mappers that can verify the position of the lens power maps, which is a relative position to the engraving reference points. There is no standard for the possible shifts of the lens power map either, which could be horizontal, vertical and rotational.

[INSIPD and INSNPD]

Do we have DCS labels for the inspection of PDs (Distance and Near)? I can't find them.

If we don't I think that we should add INSIPD for Distance PD inspection and INSNPD for Near PD Inspection

[Slaboff prism - label SLBP]

1 hour ago, tonyleblanc said:

The standard does not specify what index SLBP should be expressed in - in the opinion of others, should SLBP be expressed in PIND as with other prism labels?

 

I would agree on using PIND for SLBP