5 published verifications about Voice Coil Motor Voice Coil Motor ×
“A voice coil motor (VCM) used for smartphone autofocus has no gears and no friction.”
Smartphone autofocus VCMs are generally gearless, but they are not literally friction-free. Technical sources describe lens guides, springs, suspensions, and other contact structures that introduce friction and must be managed for precise focusing. The claim turns a real simplification—direct drive with no gears—into an inaccurate absolute.
“A piezoelectric motor can mechanically hold its position when power is cut (off-power holding), whereas a voice coil motor (VCM) requires current to hold position.”
The claim captures the usual engineering distinction. Many piezo motors can hold position off power through frictional or self-locking mechanics, whereas standard voice-coil motors are back-drivable and typically need continuous current to hold force or maintain position under load. The caveat is that this is not universal: some piezo-based actuators are not mechanically self-locking, and specialized VCM systems can achieve zero holding current with added design features.
“In a voice coil motor (VCM), the magnetic field is provided by a permanent magnet, and the lens position is controlled by varying the current through a copper coil.”
The statement accurately describes the basic operating principle of a voice coil lens actuator. In standard VCM designs, a permanent magnet supplies the static magnetic field, and changing current in the coil changes the force that moves the lens. Some implementations add springs, biasing, or feedback, but those details do not negate the claim’s core mechanism.
“A voice coil motor (VCM) autofocus module typically uses a return spring so that when current is reduced or cut, the lens moves back toward a rest position.”
The claim matches how most mainstream VCM autofocus modules are designed. Technical sources describe the lens carrier as suspended by springs or flexures, with position set by the balance between magnetic drive force and restoring force. When current is reduced or removed, the lens typically returns toward a default rest or park position, though some less common VCM variants behave differently.
“Piezoelectric autofocus motors can hold their position without continuous power, unlike voice coil motor (VCM) autofocus modules that require continuous current to hold a non-rest position.”
The claim accurately describes the usual behavior of commercial autofocus actuators. Piezoelectric autofocus motors commonly hold position without continuous power because many are self-locking, while standard VCM autofocus modules usually need current to stay at a non-rest position. The key caveat is that specialized VCM designs with zero holding current do exist, so the contrast is not universal.