Camera Module Layout to Reduce SMA Motor EMI Stripe Noise
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Solution Overview
Problem
Existing camera modules in smartphones face challenges in reducing electromagnetic interference (EMI) caused by the proximity of shape memory alloy (SMA) motors and their wiring to image sensors, leading to stripe noise in captured images.
Innovation Solution
The motor circuit board is positioned far away from the image sensor, specifically located on the object side of the camera lens assembly, increasing the physical distance between the motor circuit board and the image sensor to reduce electromagnetic interference and stripe noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor circuit board is disposed close to the image sensor to save space, then the device size is reduced, but electromagnetic interference causes stripe noise in images
Solution Approach 1:
The motor circuit board is repositioned from a planar arrangement (close to the image sensor) to a three-dimensional arrangement (above the camera lens assembly). This spatial reconfiguration in the vertical dimension increases the distance between the motor circuit board and image sensor, reducing electromagnetic interference while maintaining a compact overall module design.
Solution Approach 2:
The camera lens assembly serves as an intermediary structure that physically separates the motor circuit board from the image sensor. By positioning the motor circuit board above the camera lens assembly, the optical components act as a spatial mediator that increases the physical distance between the electromagnetic interference source and the sensitive image sensor.
2Object-affected harmful factors
If the motor circuit board is positioned far from the image sensor to reduce electromagnetic interference, then stripe noise is reduced, but the overall module size increases
Solution Approach 1:
The motor circuit board is nested above the camera lens assembly, which itself is positioned above the image sensor. This nested arrangement allows the motor circuit board to be remotely positioned from the image sensor for reduced electromagnetic interference, while the entire assembly remains compact due to the vertical stacking configuration.
Solution Approach 2:
Instead of increasing horizontal distance between the motor circuit board and image sensor (which would increase module area), the design utilizes the vertical dimension by positioning the motor circuit board above the camera lens assembly. This three-dimensional arrangement achieves electromagnetic isolation without significantly increasing the overall module footprint.
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
This configuration effectively reduces stripe noise in images by minimizing electromagnetic interference between the SMA motor circuit board and the image sensor, thereby improving image quality.
Implementation Method 1
the movement of the camera lens may be driven by using a motor driven by an SMA wire
Implementation Method 2
the SMA wire produces electromagnetic interference to the image sensor
Data Source
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AI summary
This application discloses a camera module, including: a camera lens assembly, a motor circuit board, and an image sensor, where the motor circuit board and the camera lens assembly each have a light passing hole, the camera lens assembly is located between the image sensor and the motor circuit board, a light-sensitive surface of the image sensor is located on an image side of the camera lens assembly, and the motor circuit board is located on an object side of the camera lens assembly. This application further provides a corresponding camera and a mobile terminal. In the technical solutions of this application, because the motor circuit board is disposed at a position far away from the image sensor, electromagnetic interference can be reduced, and stripe noise can be reduced.