Structure for sensing motion track of voice coil motor

Abstract

The invention discloses a structure for sensing a motion track of a voice coil motor. The voice coil motor at least comprises a yoke plate, an upper cover, a coil, a drive magnet, a bracket and a base; the voice coil motor further comprises a circuit board fixedly arranged on the inner wall of the yoke plate; the circuit board comprises a PET circuit board and an injection molding board for fixingthe PET circuit board; a Hall IC chip and a capacitor connected in parallel with the Hall IC chip are arranged on the PET circuit board; a feedback magnet matched with the Hall IC chip is arranged one side, corresponding to the Hall IC chip, of the bracket; the coil is wound outside the bracket; and the drive magnet is arranged on the periphery of the coil and does not interfere with the feedbackmagnet. The drive magnet and the coil play a role in driving vertical motion of a lens arranged in the bracket to adjust the focal length, and the feedback magnet and the Hall IC chip play a role inadjusting the current input to the coil by negative feedback, so that the motion tracks of the bracket and the lens are more accurate. The structure is low in cost and stable in performance.

Description

technical field [0001] The invention relates to a voice coil motor, in particular to a structure for sensing the movement track of the voice coil motor. Background technique [0002] Nowadays, with the development of science and technology, digital devices with photographing and video recording functions are widely used, and the above-mentioned devices usually have the function of adjusting the focal length. [0003] An existing closed-loop voice coil motor drives the lens through the interaction between the coil and the magnetic field generated by the magnet, so that the lens can move in the vertical direction, thereby realizing the focal length adjustment function of the lens, and the coil is fixed, and the magnet is dynamic. , the magnetic field strength at different points in the vertical direction will change when the magnet moves vertically, the change of the magnetic field strength is sensed by the fixed and interconnected PCB board and the Hall element, and the feedb...

AI Technical Summary

Problems solved by technology

[0004] However, because the above-mentioned closed-loop voice coil motor is dynamic, it is not only a driving magnet, but also a feedback magnet. In this way, the magnetic field generated by the current in the Hall element will affect the magnetic field of the driving magnet, and the distance between the driving magnet and the Hall element will be too large. Factors such as the influence caused by the distance will cause errors in both the drive and feedback processes

Furthermore, the circuit board of the existing voice coil motor is designed by using the FPC circuit board, which has complicated process and high processing cost

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