Camera Module Leaf Spring Load Characteristic Stabilization
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Solution Overview
Problem
The existing camera module's leaf springs have unstable load characteristics due to uneven metal plate thickness and heat treatment variations, affecting the initial response speed and displacement stability, making precise control of the holder position difficult.
Innovation Solution
Incorporating a bridge portion supporting means that can adjust the load characteristic of the leaf springs by supporting selected regions of the bridge portions, allowing for adjustment of the spring constant and effective deformable length, ensuring a stable driving force within the magnetic circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional leaf springs made from metal plates are used, then the structure is simple and easy to manufacture, but the load characteristic is unstable due to uneven metal plate thickness and heat treatment variations
Solution Approach 1:
The leaf spring is divided into multiple bridge portions (first, second, third bridge portions) with different thicknesses. Each bridge portion has a specific thickness designed to compensate for uneven metal plate thickness in different regions, allowing the overall structure to maintain stable load characteristics despite manufacturing variations in the metal plate
Solution Approach 2:
Different regions of the leaf spring are given different thicknesses to optimize local performance. The first bridge portion has a first thickness, the second bridge portion has a second thickness, and the third bridge portion has a third thickness, where these thicknesses are specifically designed to compensate for local variations in metal plate thickness and achieve uniform load characteristics across all bridge portions
2Strength
If the metal plate thickness is increased to improve strength, then the strength increases, but the initial response speed decreases due to increased mass
Solution Approach 1:
The leaf spring employs non-uniform thickness distribution across different bridge portions. Each bridge portion is given a specific thickness (first, second, and third thicknesses) that provides sufficient local strength while minimizing unnecessary mass. This localized optimization allows the structure to achieve required strength without the penalty of uniformly increasing thickness throughout the entire leaf spring
Solution Approach 2:
The different thicknesses of the bridge portions create different spring constants (first, second, and third spring constants) that are optimized for their specific locations and load conditions. This dynamic optimization of stiffness distribution allows the leaf spring to respond more quickly to applied forces while maintaining the necessary strength
3Force
If the spring constant is increased to improve holding force, then the driving force stability improves, but the displacement flexibility decreases
Solution Approach 1:
The leaf spring is designed with different spring constants for different bridge portions, allowing each portion to contribute differently to the overall force characteristics. The first, second, and third spring constants are optimized to work together to provide stable driving force while maintaining the necessary displacement flexibility for the lens unit to move through its required range
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 solution stabilizes the driving force of the holder in the magnetic circuit by adjusting the leaf spring's load characteristic and spring constant, even with uneven metal plate thickness and magnet variations, ensuring precise control of the holder's position.
Implementation Method 1
achieved by an interaction between a magnetic field generated by an electrical current flowing in a coil and a magnetic field generated by a yoke and magnets provided on the yoke
Implementation Method 2
By supplying a current to the coil 107 to generate a magnetic field, a driving force for displaying the holder 108 in a direction of an optical axis of the lens unit is generated
Implementation Method 3
By resilient deformation of the respective three bridge portions 104c and 110c, the holder 108 can be displaced in a direction of an optical axis of the lens unit
Data Source
AI summary
A camera module includes upper and lower leaf springs having a stable load characteristic and a holder displaceably held by the leaf springs so that the holder can be stably displaced within a magnetic circuit. The upper spring has an outer annular portion, an inner annular portion provided inside the outer annular portion so as to be displaceable with respect to the outer annular portion and attached to the holder, and a plurality of bridge portions coupled between the outer annular portion and the inner annular portion. The camera module further includes a bridge portion supporting member for supporting a part of at least one of the plurality of bridge portions so that a load characteristic of the leaf spring can be changed.