Titanium Copper Foil Composition for Uniformly Etched Camera Springs
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Solution Overview
Problem
Conventional titanium copper foils used in autofocus camera modules lack sufficient strength in multiple directions and exhibit non-uniform etching, which affects their performance and reliability as conductive spring materials.
Innovation Solution
Incorporating specific amounts of Fe and controlling the production process through solutionizing, preliminary aging, and multiple cold rolling stages to achieve a balanced strength and uniform etching in three directions, including parallel, perpendicular, and 45° relative to the rolling direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional titanium copper foil is used to reduce raw material costs, then cost is reduced, but strength is insufficient causing settling
Solution Approach 1:
The invention changes the chemical composition parameters by adding Fe (10-3000 ppm) to the titanium copper foil, transforming it from a conventional Ti-Cu alloy to a Fe-containing Ti-Cu alloy. This parameter change enables the material to achieve both cost-effectiveness and sufficient spring strength (1100 MPa or more) without settling, resolving the contradiction between cost reduction and reliability
Solution Approach 2:
The invention creates a composite alloy system by combining Cu, Ti, and Fe elements with specific concentration ratios. The Fe element acts as a strengthening phase distributed within the Cu-Ti matrix, forming a composite material structure that provides both economic advantage and mechanical performance required for autofocus spring members
2Strength
If cold rolling is performed at high rolling reduction ratio to increase strength, then strength increases, but etching uniformity deteriorates
Solution Approach 1:
The invention changes the material composition parameters by adding Fe, which modifies the etching behavior and crystal structure of the alloy. This enables the material to maintain etching uniformity (Cpk ≥ 1.00) even after high rolling reduction ratio cold rolling (90-99%), achieving both high strength (1100 MPa or more) and good etching uniformity simultaneously
Solution Approach 2:
The Fe element acts as an intermediary that mediates between the conflicting requirements of high strength and good etching uniformity. By controlling Fe concentration within 10-3000 ppm, the invention creates a balanced alloy structure where Fe particles distribute uniformly, serving as nucleation sites that maintain etching uniformity while the cold rolling process develops the required strength
3Strength
If multiple heat treatment stages are applied to increase strength, then strength improves, but process complexity increases
Solution Approach 1:
The invention performs preliminary action by adding Fe to the alloy composition before the main production process. This compositional preparation enables the subsequent cold rolling and heat treatment processes to achieve high strength (1100 MPa or more) more effectively, reducing the need for multiple complex heat treatment stages and simplifying the overall production process while maintaining or improving 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 resulting titanium copper foil achieves tensile strengths of 1100 MPa or more in all relevant directions with improved etching uniformity, ensuring reliable performance as a conductive spring material for autofocus camera modules.
Implementation Method 1
a solutionizing treatment, preliminary aging, and cold rolling are carried out in this order
Implementation Method 2
a solutionizing treatment, preliminary aging, and cold rolling are carried out in this order
Data Source
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AI summary
Provided is a titanium copper foil which has required high strength when used as a spring, and has improved etching uniformity, and which can be suitably used as a conductive spring material for use in electronic device parts such as autofocus camera modules. The titanium copper foil contains from 1.5 to 5.0% by mass of Ti and from 10 to 3000 pm by mass of Fe, the balance being Cu and inevitable impurities, wherein the titanium copper foil has crystal orientation having A of from 10 to 40, in which A is represented by the following equation (1) when measuring a rolled surface by an X-ray diffraction method: A=β220/β200+β311 in which the β {220}, the β {200}, and the β {311} represent half-value widths of X-ray diffraction peaks at a {220} crystal plane, a {200} crystal plane, and a {311} crystal plane, respectively.