Titanium-Copper Foil Spring for Camera Module Impact Resistance
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Solution Overview
Problem
Camera modules with spring members that exceed their elastic limit due to impacts, such as drops, can permanently deform, leading to malfunction in automatic focusing operations.
Innovation Solution
A camera module using a titanium-copper foil spring member with a Vickers hardness of 350 or higher and a thickness between 0.01 and 0.1 mm, where the Ti concentration at 0.1 μm from the surface is at least 0.6 times that at 1 μm, reducing the likelihood of permanent set and malfunction upon impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring member is used to urge the lens toward the initial position, then the automatic focusing operation can be performed, but the spring member may exceed its elastic limit and become permanently deformed when subjected to strong impacts
Solution Approach 1:
The patent applies parameter changes by specifying precise compositional parameters (Ti content: 2.9-3.5% by mass) and physical parameters (Vickers hardness: 350 or higher, thickness: 0.01-0.1 mm) of the titanium-copper foil to optimize its elastic properties and resistance to permanent deformation under impact
Solution Approach 2:
The patent uses composite materials by employing a titanium-copper alloy foil instead of pure copper or other single-metal springs. The titanium-copper composite structure provides superior elastic recovery characteristics and resistance to permanent set compared to conventional spring materials
2Strength
If the Vickers hardness of the titanium copper foil is increased to improve permanent set resistance, then the spring member becomes more resistant to deformation, but the manufacturing precision and surface quality may be affected
Solution Approach 1:
The patent resolves this contradiction by precisely controlling multiple parameters simultaneously: Ti content (2.9-3.5% by mass), Vickers hardness (350 or higher), and thickness (0.01-0.1 mm). This multi-parameter optimization ensures high permanent set resistance while maintaining manufacturability and surface quality
Solution Approach 2:
The patent applies local quality by specifying the Ti concentration distribution through thickness, requiring that the Ti concentration at 0.1 μm from the surface be at least 0.6 times that at 1 μm from the surface. This ensures optimal surface properties for elasticity while maintaining bulk strength
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 titanium-copper foil spring member effectively limits permanent set and reduces the risk of malfunction in camera modules when subjected to impacts, ensuring reliable automatic focusing operations.
Implementation Method 1
a spring member which elastically urges a lens toward an initial position along an optical axis direction
Implementation Method 2
electromagnetic drive means capable of driving the lens along the optical axis direction by producing an electromagnetic force against the urging force of the spring member
Data Source
AI summary
A camera module (1) which includes a lens (3); a spring member (9a, 9b) which elastically urges the lens (3) toward an initial position along an optical axis direction; an electromagnetic drive means (11) capable of driving the lens (3) along the optical axis direction by producing an electromagnetic force against an urging force of the spring member (9a, 9b); and a control means (12) configured to control a drive current supplied to the electromagnetic drive means (11), wherein the spring member (pa, 9b) contains 2.9% to 3.5% by mass of Ti, with the balance being copper and inevitable impurities, and has a Vickers hardness equal to or greater than 350.