Lens Driver Cover Layout for Stronger AF Force and Lower Magnetic Interference
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Solution Overview
Problem
Existing camera modules face challenges in improving electromagnetic force between the coil and magnet unit and suppressing magnetic field interference between the sensing magnet and the magnet unit, particularly in subminiature, low-power camera modules.
Innovation Solution
A lens driving device is designed with a cover member made of magnetic material, where the magnet units are disposed adjacent to the edges of the side plate and the cover member includes openings to face the sensing magnet, enhancing electromagnetic force and reducing magnetic field interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If magnet units are disposed adjacent to edges of the side plate to improve electromagnetic force, then electromagnetic force between coil and magnet unit is improved, but magnetic field interference between sensing magnet and magnet unit increases
Solution Approach 1:
The patent extracts the harmful magnetic field interference by introducing openings in the side plate that allow the magnetic field from the sensing magnet to pass through to the position sensor, separating the sensing path from the driving magnet units. This enables the sensing function to operate independently without interference from the drive magnets.
Solution Approach 2:
The openings in the side plate act as intermediaries that facilitate the magnetic field transmission from the sensing magnet to the position sensor. These openings mediate between the sensing system and the driving system, allowing the sensing magnet's field to reach the sensor while the drive magnet units remain positioned to provide electromagnetic force.
2Volume of moving object
If camera module size is reduced for subminiature applications, then adaptability to small electronic products is improved, but electromagnetic force between coil and magnet unit deteriorates
Solution Approach 1:
The patent applies local quality by positioning the magnet units specifically at the corner portions of the housing, maximizing their electromagnetic interaction with the coil in the limited space. This strategic local placement ensures that the electromagnetic force is concentrated where most needed, compensating for the overall reduced size of the camera module.
Solution Approach 2:
The patent utilizes the three-dimensional space efficiently by arranging magnet units at corner portions and using openings in the side plate, effectively using vertical and lateral dimensions to optimize both electromagnetic force and magnetic field separation without increasing the overall footprint of the camera module.
3Object-affected harmful factors
If openings are formed in the side plate to reduce magnetic field interference, then magnetic field interference is suppressed, but structural strength of the side plate deteriorates
Solution Approach 1:
The side plate is segmented by forming openings in it, dividing the plate into sections that maintain structural integrity while allowing magnetic field transmission. The openings are strategically positioned to provide the necessary magnetic field access without compromising the overall structural strength of the side plate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves the electromagnetic force between the magnet unit and the coil, while suppressing magnetic field interference, thereby ensuring reliable autofocus operation and maintaining the stability of the camera module.
Implementation Method 1
a coil disposed on the bobbin and facing the magnet units
Implementation Method 2
a position sensor disposed in the cover member so as to face the sensing magnet
Data Source
AI summary
This invention includes a cover member comprising a upper plate and side plates, a bobbin disposed in the cover member, magnet units disposed in the cover member a coil which is disposed on the bobbin and faces the magnet units, a sensing magnet disposed on the bobbin, and a position sensor which is disposed in the cover member and faces the sensing magnet, wherein the magnet units are disposed adjacent to respective edges between side plates of the cover member, and the cover member has a first opening formed on a side plate thereof such that the first opening faces the sensing magnet.