Photolithographic dials and moiré indicators for watches and micro-mechanics

Why photolithography for small dials and indicators

Printing and pad-printing reach their limit around fine lines and small numerals. Photolithography — the process used for optical encoder discs — patterns a thin film through a photomask, so lines, scale marks and numerals come out with sharp edges and uniform pitch, all in one layer and aligned to each other.

Moiré indicators in one paragraph

Two radial gratings with slightly different line counts, laid over each other, produce a moiré pattern: a small rotation of one disc moves broad light/dark bands by a much larger amount. In watches and instruments this gives a visual indicator, a vernier-like read-out or a decorative effect driven by a very small motion.

Substrates and appearance

• Chrome on glass – our core process; high contrast, flat and stable
• Dark / anti-reflective chrome (e.g. CrOx/Cr/CrOx), including dark from both sides – reviewed per drawing
• Thin glass (e.g. 0.10–0.15 mm) and film – reviewed per drawing
• Laser outer diameter and bore centred on the pattern – critical for moiré pairs

Exact line width, thickness and tolerance are confirmed in the quotation for each part; we do not publish numbers we have not confirmed for your geometry.

What to send

GDSII photomask masters (or DXF / 1:1 SVG), substrate and thickness, diameter and bore, line count and line width at a stated radius, appearance of each side, centering tolerance, quantities (samples, 100 / 300 / 1,000).

Start small

A practical first step is photomasks plus a bench test of the moiré effect before ordering samples. Read an anonymised example: two-side-dark thin-glass radial grating.

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