Stepped Lens Barrel VCM for Compact Camera Module Focusing
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Solution Overview
Problem
Camera modules with voice-coil motors (VCM) face challenges in miniaturization due to the increased size caused by the VCM surrounding the lens part, which hinders the compact design of camera modules.
Innovation Solution
The camera module design features a VCM that is coiled around a lens barrel with a stepped structure, allowing the VCM to be sleeved without increasing the outer diameter of the lens part, utilizing a winding and permanent magnet members to focus the lens by moving it towards or away from the image sensor, while maintaining compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voice-coil motor is used to drive the lens part, then focusing functionality is achieved, but the overall size of the camera module increases
Solution Approach 1:
The VCM is nested within the lens barrel structure, with the winding coiled around the upper portion and the magnet members positioned inside the lens holder. This nesting allows the VCM components to occupy space within the existing lens assembly rather than adding external volume, resolving the contradiction between achieving focusing functionality and maintaining compact size.
Solution Approach 2:
The lens barrel employs a stepped structure with different diameters at different heights, allowing the VCM to be arranged in a vertical dimension rather than expanding the horizontal footprint. The upper portion has a smaller diameter to accommodate the coiled winding, while the lower portion maintains the original outer diameter, enabling the VCM to function without increasing the camera module's overall size.
2Ease of operation
If the VCM surrounds the lens part, then lens control is achieved, but the outer diameter of the lens part increases
Solution Approach 1:
The lens barrel is designed with an asymmetric stepped structure where the upper portion has a smaller diameter than the lower portion. This asymmetry allows the VCM winding to be coiled around the upper portion without increasing the overall outer diameter, while still providing sufficient space for the winding and magnet members to function. The lower portion maintains the original diameter to preserve compactness.
Solution Approach 2:
The lens holder is designed with localized features including a recess at the upper end and positioning protrusions that accommodate the VCM components at specific locations. The magnet members are positioned at specific locations within the lens holder, allowing lens control functionality to be achieved at local positions without requiring the entire lens assembly to be enlarged.
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 design enables the camera module to achieve focusing functionality without enlarging the camera module's size, thereby supporting miniaturization efforts and maintaining effective lens control.
Implementation Method 1
When applying different directions of current to the winding, the winding, magnetically forced by the magnetic members, can focus the lens part by moving it toward or away from the image sensor
Data Source
AI summary
A camera module includes an image sensor, a substrate, a lens part, a lens holder, and a voice-coil motor (VCM). The image sensor is supported on and electrically connected to the substrate. The lens holder has a bottom end and an upper end opposite to the bottom end. The image sensor is accommodated within the lens holder. The lens part includes a lens barrel which has an upper portion and a bottom portion and is disposed on the lens holder. The VCM includes a winding coiling around the upper portion and a set of permanent magnetic members fixedly fixed and surrounding the winding. The outer diameter of the upper portion is smaller than that of the bottom portion. The VCM is configured for driving the lens part to move toward to or away from the image sensor.