Case: Evaluating a two-side-dark thin-glass radial grating for a European customer

The request

A European product company sent a request for a matched pair of small radial gratings that work together to form a moiré pattern:

• Part A – a radial grating with scale marks and numerals on a thin polymer film
• Part B – a radial grating on thin glass, required to be dark from both sides (an anti-reflective CrOx/Cr/CrOx type stack)
• Both patterns centred tightly on the bore; files supplied as GDSII photomask masters, DXF and 1:1 SVG, with a bilingual specification

Customer name, dimensions and prices are confidential and not shown here.

How we review a request like this

1. File check – open the GDSII masters, confirm layers, line count, line width at the stated radius and the scale/numeral layer.
2. Process match – Part B is close to our chrome-on-glass encoder disc process (photolithography, etching, laser OD and laser bore centred on the pattern). The open points are the thin substrate and the two-side-dark coating stack — both are reviewed against the drawing, not promised in advance.
3. Part A on film – reviewed separately, because film handling, coating adhesion and printing on the back side differ from glass.
4. Staged quotation – we propose to start with the photomasks and a bench test (step 0) before samples and volume, so the customer verifies the moiré effect with minimum one-time cost.
5. Written answers – which part we can make, with which process, the minimum line width we guarantee, one-time costs, unit prices for samples and volumes, and lead times.

Why this matters to buyers

Moiré pairs are unforgiving: a few micrometres of eccentricity or a line-width drift shows up directly in the pattern. Review the pattern-to-bore centering, line width at the inner radius and coating appearance on each side with the supplier before ordering masks.

Have a similar part? Send the files — NDA available.

→ Radial grating & moiré discs · Chrome-on-glass · RFQ · sales@enc7.com (NDA)