Why reflective metal and absolute patterns
- Thin and robust. With a reflective metal encoder disc the light source and detector sit on one side, so the encoder can be made thinner — important in collaborative robot joints. Metal does not shatter under shock or collision.
- Absolute position. A joint must know where it is after a power loss without homing. Absolute discs use multi-track Gray code or a single pseudo-random track; see incremental vs absolute encoder discs.
- Hollow shafts. Large-bore discs leave room for cables through the joint.
What to specify
Bit count and code type, reading radius of each track, readhead or decoder chip model, readhead wavelength, high/low reflectance requirements, bore and outer diameter, operating temperature. Use our RFQ checklist.