Strong conventional magnets are a problem inside thin devices. Their fields extend well beyond the magnet, so they can disturb a compass or magnetometer, interfere with nearby sensors, and wipe the magnetic stripe on a card that rests against the product.
Patterned magnets reduce that reach. Correlated Magnetics Research says the same process that concentrates a Polymagnet's force near its surface also minimizes stray fields where they are not wanted, and that its magnets are designed not to interfere with sensitive electronics or damage credit cards. Its attach design note adds that, unlike conventional magnets, the reach of a Polymagnet's field can be set to suit the design rather than growing with strength.
CMR also covers other tools for this in its advanced webinar: taming fields near compasses and cards, and using shunts (steel pieces that carry flux) to raise strength and cut interference. A NASA Armstrong report reposted on CMR's blog makes a related point, that printed magnetic poles keep loops tight and reduce electromagnetic interference concerns.
Short reach is a design input, not a guarantee. Measure the field at the sensor location with a gaussmeter in your actual layout, including any steel nearby, before signing off.
WholeMagnetics, 2026-10-04. Polymagnet facts are taken from Correlated Magnetics Research’s public pages, listed below; vendor performance figures are CMR’s own.