Spring Metal Foil Thickness Control for Etched Leaf Spring Consistency
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Solution Overview
Problem
The challenge lies in achieving uniform thickness in high-hardness metal foils for leaf springs used in camera module drive mechanisms, as variations in thickness lead to inconsistencies in spring load and deflection, necessitating precise control of thickness variations to minimize spring width variations in the thickness direction.
Innovation Solution
A metal foil with a specific condition where the absolute difference in standard deviation of thickness in the width direction orthogonal to the rolling direction is less than or equal to 0.15 μm, ensuring uniformity and limiting variations in spring width, achieved through controlled rolling and annealing processes, allowing for consistent spring load and deflection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-hardness metal is used for the leaf spring to satisfy spring load and deflection requirements, then the spring load and deflection performance is improved, but the manufacturing precision of the metal foil thickness deteriorates
Solution Approach 1:
The patent changes the material parameters by specifying a particular hardness range (HV 180 to HV 280) and controlling the thickness uniformity through standardized deviation metrics. This parameter optimization allows the high-hardness metal to achieve both the required spring performance and acceptable manufacturing precision for thin foil applications.
2Volume of moving object
If the metal foil is thinned to a predetermined thickness through rolling to reduce the volume of the leaf spring, then the volume is reduced, but the manufacturing precision of the thickness uniformity deteriorates
Solution Approach 1:
The patent replaces traditional mechanical thickness measurement and control methods with a statistical approach using standardized deviation calculations. By evaluating thickness distribution through statistical parameters rather than simple point measurements, the system can achieve better control over thickness uniformity in thin foils while maintaining reduced volume.
3Manufacturing precision
If variations in the thickness of the metal foil are minimized to reduce variations in the width of the leaf spring after wet-etching, then the spring width consistency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary thickness uniformity evaluation and selection before the wet-etching process. By calculating standardized deviations and selecting metal foils that meet specific criteria in advance, the system ensures consistent spring width after etching without adding complexity to the etching process itself. The preliminary selection prevents variations from propagating through subsequent manufacturing steps.
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 approach results in a metal foil that maintains consistent spring width variations, enhancing the reliability and durability of the spring member by preventing excessive isotropic etching, thus ensuring precise shape formation and improved performance in camera module drive mechanisms.
Implementation Method 1
A metal foil, which is the raw material for the leaf spring, is thinned to a predetermined thickness through rolling
Implementation Method 2
The leaf spring is formed by wet-etching a metal foil
Data Source
AI summary
A metal foil for a spring member includes a first region on which the spring member is formed. The first region has a square shape with one side being 300 mm. In the first region, an absolute value of a difference value obtained by subtracting a standard deviation of a thickness in a width direction orthogonal to a rolling direction from a standard deviation of a thickness in the rolling direction is less than or equal to 0.15 μm.