US12571656USUSPTO Grant XML

Position detection device, camera module, and rotary actuator

A position detection device includes a magnetic field generator and a magnetic sensor. The magnetic field generator is configured so that a mode of variation of a direction of a target magnetic field relative to variations in a position of a lens is such that the direction of the target magnetic field varies nonlinearly relative to the variations in the position of the lens. The magnetic sensor is configured so that a mode of variation of a detection signal relative to variations in the direction of the target magnetic field is such that the detection signal varies nonlinearly relative to the variations in the direction of the target magnetic field.

Patent

Brief

Patent brief

Problem

How can vibration in electric motors and rotors be reduced?

Novelty

The magnetic field generator is configured so that a mode of variation of a direction of a target magnetic field relativ...

Uses

Motor control, Precision machinery, Electromechanical systems

Assignee

TDK CORPORATION

Published

Mar 10, 2026

Inventors

Yongfu Cai

Domain

Electromechanical systems

Plain-English summary

Problem

How can vibration in electric motors and rotors be reduced?

Solution

position detection device includes a magnetic field generator and a magnetic sensor.

Key novelty

The magnetic field generator is configured so that a mode of variation of a direction of a target magnetic field relative to variations in a position of a lens is such that the direction of the target magnetic field varies nonlinearly relative to the variations in the position of the lens.

Applications

Motor controlPrecision machineryElectromechanical systems

Relevant search intents

actuator

Claims preview

1 . A magnetic sensor configured to: detect a target magnetic field such that a mode of variation of a direction of the target magnetic field varies nonlinearly relative to positions of a detected magnetic object, over an entire range of the positions of the detected magnetic object; and generate a detection signal corresponding to the direction of the target magnetic field, wherein a mode of variation of the detection signal relative to variations in the direction of the target magnetic field varies nonlinearly relative to the variations in the direction of the target magnetic field, and the detection signal varies linearly relative to positions of the detected magnetic object. 2 . The magnetic sensor according to claim 1 , wherein: a target angle that the direction of the target magnetic field forms with respect to a reference direction in a reference plane varies within a first variable range; and the detection signal varies within a second variable range corresponding to the first variable range. 3 . The magnetic sensor according to claim 2 , comprising: a resistor; a power supply port; a ground port; an output port; a first magnetoresistive element located between the power supply port and the output port; and a second magnetoresistive element located between the output port and the ground port, wherein: the resistor is either connected in series to the first magnetoresistive element so that the resistor is located between the power supply port and the output port, or connected in series to the second magnetoresistive element so that the resistor is located between the output port and the ground port; each of the first and second magnetoresistive elements includes a magnetization pinned layer having a first magnetization that is parallel to the reference plane and fixed in direction, and a free layer having a second magnetization that is parallel to the reference plane and whose direction is variable according to the direction of the target magnetic field; the direction of the first magnetization of the magnetization pinned layer in the first magnetoresistive element is a first direction; the direction of the first magnetization of the magnetization pinned layer in the second magnetoresistive element is a second direction opposite to the first direction; and the detection signal depends on a potential of the output port.

Linked approaches

Active control systems

Control loops that counter vibration using sensing and actuation.

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