Grain-Zoned Metal Back Plate for Warpage and Crack Resistance
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Solution Overview
Problem
The use of O-state and H38-state aluminum-magnesium alloys for metal back plates in electronic devices leads to appearance defects such as warpage and cracks, reducing manufacturing yield due to their lower hardness and elongation compared to stainless steel, while replacing stainless steel with these alloys aims to reduce device weight.
Innovation Solution
A metal back plate with distinct areas of different grain sizes, where the first area has a larger grain size for greater elongation and the second area has a smaller grain size for higher hardness, is manufactured using a process involving annealing treatments and cutting/punching to minimize defects and maintain weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If O-state aluminum-magnesium alloy is used for metal back plate, then weight is reduced, but appearance defects such as warpage occur due to lower hardness and elongation
Solution Approach 1:
The patent applies local quality by creating distinct grain size zones within the metal back plate: a first area with larger grain size for improved elongation and crack resistance, and a second area with smaller grain size for enhanced hardness and warpage resistance. This spatial differentiation of microstructural properties allows different regions to exhibit optimized mechanical characteristics suitable for their specific functional requirements, thereby resolving the contradiction between weight reduction and appearance quality.
Solution Approach 2:
The patent segments the metal back plate into multiple areas with different grain sizes through selective annealing treatment. By dividing the uniform structure into heterogeneous zones, the plate can simultaneously exhibit both high elongation (in the first area) and high hardness (in the second area), overcoming the limitation of using a single material state throughout the entire component.
2Strength
If H38-state aluminum-magnesium alloy is used for metal back plate, then hardness is improved, but cracks occur due to lower elongation
Solution Approach 1:
The patent applies local quality by creating distinct grain size zones within the metal back plate: a first area with larger grain size for improved elongation and crack resistance, and a second area with smaller grain size for enhanced hardness and warpage resistance. This spatial differentiation of microstructural properties allows different regions to exhibit optimized mechanical characteristics suitable for their specific functional requirements, thereby resolving the contradiction between weight reduction and appearance quality.
Solution Approach 2:
The patent segments the metal back plate into multiple areas with different grain sizes through selective annealing treatment. By dividing the uniform structure into heterogeneous zones, the plate can simultaneously exhibit both high elongation (in the first area) and high hardness (in the second area), overcoming the limitation of using a single material state throughout the entire component.
3Strength
If stainless steel is used for metal back plate, then mechanical strength is improved, but weight increases
Solution Approach 1:
The patent applies parameter changes by modifying the grain size parameter through selective annealing treatment to achieve the desired balance between mechanical strength and weight. By controlling the grain size in different areas, the aluminum-magnesium alloy back plate can attain mechanical properties comparable to stainless steel while maintaining the weight advantage of aluminum alloys.
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 solution enhances the mechanical strength and hardness of the metal back plate, reducing defects like warpage and cracks, thereby improving production yield and maintaining weight reduction without increasing the back plate's weight or altering the opening's position.
Implementation Method 1
placing the second section in annealing equipment to perform a first annealing treatment
Data Source
AI summary
The present disclosure provides a metal back plate and a manufacturing process thereof, a backlight module and an electronic device. The metal back plate is used for the backlight module. The metal back plate includes a first area and a second area. The grain size of the metal material in the first area is larger than the grain size of the metal material in the second area. The first area is formed with a first opening.