Radial grating · Moiré pairs · Photolithography to drawing
Custom radial grating & moiré discs
A radial grating is a disc carrying lines that run outward from the centre at a constant angular pitch. Two radial gratings with slightly different line counts, laid over each other, produce a moiré pattern that magnifies small rotations — used in indicators, optical encoders, metrology and decorative or horological mechanisms. ENC7 makes such discs with the same photolithography, chrome-on-glass and laser contour process used for our optical encoder discs.
Also searched as: radial grating disc · moiré disc / moiré pattern disc · radial line photomask disc · circular grating · polar grating
- Radial line patterns by photolithography and etching — uniform angular pitch
- Chrome on glass; anti-reflective dark chrome stacks (e.g. CrOx/Cr/CrOx) reviewed per drawing
- Glass and film substrates; thin glass (e.g. 0.10–0.15 mm) reviewed per drawing
- Laser OD cutting and laser bore machining, centred on the pattern
- Scale marks, numerals and alignment marks in the same layer
- 100% AOI inspection
Send drawing (GDSII / DXF / SVG) to sales@enc7.com — NDA available.
Photomask masters (GDSII), DXF, 1:1 SVG or PDF are all fine. An engineer reviews manufacturability and replies with a quotation. Prefer a form? Request a quote.
Photomask masters (GDSII), DXF, 1:1 SVG or PDF are all fine. An engineer reviews manufacturability and replies with a quotation. Prefer a form? Request a quote.
Specifications
| Parameter | Radial Grating / Moiré Disc |
|---|---|
| Pattern | Radial lines, scale marks, numerals — single grating or matched moiré pair, from your GDSII / DXF / SVG |
| Substrates | Optical glass (chrome on glass); thin glass and polymer film (PC; PET on request) — confirmed at drawing review |
| Coating | Chrome (Cr); dark / anti-reflective stacks such as CrOx/Cr/CrOx and two-side-dark — per drawing, confirmed in the quotation |
| Line width, line count, diameter | Per drawing — minimum guaranteed line width stated in the quotation |
| Pattern-to-bore centering | Laser bore centred on the pattern; tolerance per drawing, confirmed in the quotation |
| Inspection | 100% AOI machine vision; vision measuring machine; optical density / reflectance testing |
| Files accepted | GDSII photomask masters, DXF, DWG, 1:1 SVG, PDF |
What we can customize
- Line count and line width (constant or tapering with radius)
- Outer diameter, bore and thickness to drawing
- Second grating with a different line count to form a moiré pair
- Front / back appearance (bright chrome, dark both sides)
Ordering information
| Quotation | Engineer reviews your files for manufacturability; quotes one-time costs (photomask, set-up), sample and volume pricing and lead times |
|---|---|
| Minimum order quantity (MOQ) | 100 pcs for production; samples and photomask-only starts can be discussed |
| Confidentiality | NDA available on request |
| Manufacturer | ENC7 — Langfang Jingzheng Optoelectronic Technology Co., Ltd., factory-direct since 2007 |
Typical applications
What we need from you
- Pattern files: GDSII photomask master, DXF or 1:1 SVG (PDF for reference)
- Substrate and thickness (glass, thin glass, film), outer diameter and bore
- Line count, line width at a stated radius, coating and appearance (bright / dark, one or both sides)
- Centering tolerance between pattern and bore
- Quantities: samples, 100 / 300 / 1,000 pcs, target date
Case study & watch applications
- Case: two-side-dark thin-glass radial grating for a European customer
- Photolithographic dials and moiré indicators for watches and micro-mechanics
Translations
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Questions? Email sales@enc7.com (NDA available) or request a quote.
Glass vs. reflective metal vs. PC encoder discs
| Criterion | Glass (chrome on glass) | Reflective metal | PC (polycarbonate) |
|---|---|---|---|
| Typical optical path | Transmissive | Reflective (source and detector on the same side) | Transmissive |
| High line counts / absolute multi-track | Easiest | Possible, limited by etching and coating | Moderate resolution |
| Thermal expansion (approx.) | Low — about 3.3 (borosilicate) to 9 (soda-lime) ×10⁻⁶/K | Higher — stainless steel about 16–17 ×10⁻⁶/K | Highest — about 65–70 ×10⁻⁶/K |
| Shock and vibration | Sensitive to drops and impact | Very good — does not shatter | Good — tough, not brittle |
| Encoder height | Needs space on both sides | Can be very thin | Needs space on both sides |
| Relative cost | Higher | Lower than glass | Lowest |
| Best for | CNC, rotary tables, metrology, high-resolution servo | Robot joints, slim servo motors, hollow-shaft encoders | High-volume, cost- and weight-sensitive encoders |
Full comparison: Reflective metal or glass encoder disc? How to choose
Quality control on every disc
- 100% AOI — automated optical inspection of graduation integrity, pitch and surface defects (scratches, spots, chips).
- Vision measuring machine — critical dimensions such as outer diameter, bore and pattern-to-bore concentricity are verified.
- Optical density testing — transparent and opaque areas are measured on transmissive discs.
- ISO 9001 quality management system, certified since 2012; ISO 14001 environmental management system.
- MOQ 100 pcs, standard lead time 5–7 days.
Frequently asked questions
Can you make a matched moiré pair of radial gratings?
Yes — send both patterns (e.g. 360 and 366 lines) as GDSII or DXF. We review both parts together, including how the pair is centred, and quote each part.
Can you make a dark, anti-reflective chrome (CrOx/Cr/CrOx) that is dark from both sides?
Send the drawing with the reflectance target. Coating stack, darkness on each side and reflectance are confirmed in the quotation after engineering review.
Do you work on thin glass (0.10–0.15 mm) or film?
Send the thickness and diameter. Thin substrates and film are reviewed per drawing; feasibility, yield and price are stated in the quotation.
What is the minimum line width?
It depends on substrate, diameter and coating. We state the minimum line width we guarantee in the quotation for your specific part.
Do you sign an NDA?
Yes. Ask for our NDA or send yours to sales@enc7.com before sharing files.
Downloads
- Radial Grating / Moiré Disc datasheet (PDF) · available on request: sales@enc7.com
- RFQ checklist: 20 parameters to send with your drawing
Last updated 31 October 2026 · ENC7 Engineering Team