Code disk · grating disc
Code Disc
A code disc (code disk) is the term common on engineering drawings and in technical literature for the patterned disc of an optical rotary encoder. Its radial pattern of light and dark — or high- and low-reflectance — areas is the measuring scale: line count sets the base resolution, edge quality sets signal quality, and pattern-to-bore concentricity sets accuracy.
Also searched as: code disk · encoder code disc · optical code disc · grating disc · encoder disc
- Made to your drawing or sample
- Chrome-on-glass, reflective stainless steel or PC
- Incremental, absolute and sin/cos tracks
- Engineer review for manufacturability before quoting
- 100% AOI, vision measuring machine
Specifications
| Parameter | Code Disc |
|---|---|
| Substrates | Optical glass (chrome on glass) · stainless steel · polycarbonate (PC) |
| Optical path | Transmissive · reflective |
| Encoding | Incremental (A/B, Z) · absolute · sine/cosine |
| Dimensions, line count | To your drawing |
| Pattern process | Photolithography + etching |
| Contour machining | Laser OD cutting · laser bore machining |
| Inspection | 100% AOI machine vision; vision measuring machine; optical density / reflectance testing |
| Capacity | About 30,000 discs per day (all product lines combined) |
What we can customize
- Outer diameter, bore and thickness
- Line count, reading radius and track layout
- Absolute code type (Gray code / pseudo-random)
- Coatings and protective layers
- Inspection report contents
Ordering information
| Quotation | Engineer reviews your drawing for manufacturability, then quotes with sample and production lead times |
|---|---|
| Minimum order quantity (MOQ) | 100 pcs |
| Standard lead time | 5–7 days (confirmed in the quotation) |
| Certifications | ISO 9001 (since 2012) · ISO 14001 |
| Manufacturer | ENC7 — Langfang Jingzheng Optoelectronic Technology Co., Ltd., factory-direct since 2007 |
Typical applications
From drawing to finished code disc
- Drawing review — an engineer checks manufacturability and replies with a quotation and lead time.
- Pattern — chrome coating (glass) or reflective/absorbing films (metal), then photolithography and etching.
- Contour — laser OD cutting and laser bore machining.
- Inspection — 100% AOI plus vision measurement of OD, bore and concentricity.
Send your drawing to sales@enc7.com, WhatsApp +86 139 1091 6872, 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
What is the difference between a code disc and an encoder disc?
None — the terms are interchangeable. “Code disc” is more common on drawings and in literature; “encoder disc” and “code wheel” in catalogs.
How are code disc outer diameter, bore and thickness chosen?
They follow from the reading radius, the shaft or hub and the readhead gap. See how to set outer diameter, bore and thickness.
How should I inspect code discs at incoming inspection?
Check dimensions, pattern-to-bore concentricity, line integrity and surface defects, and the optical contrast. See encoder disc incoming inspection.
What are the MOQ, lead time and certifications?
MOQ 100 pcs, standard lead time 5–7 days, ISO 9001 and ISO 14001 certified.
Downloads
- Code Disc datasheet (PDF) · available on request: sales@enc7.com
- RFQ checklist: 20 parameters to send with your drawing
Last updated 21 October 2026 · ENC7 Engineering Team