Sapphire Cover Polishing for Curved Surfaces
Solution Overview
Problem
Conventional glass screens in electronic devices are susceptible to damage from impacts, such as drops or crushing, leading to scratches, chips, or cracks, which can render the devices inoperable, and sapphire, with its superior hardness, is challenging to process due to its hardness, especially for curved or non-planar surfaces.
Innovation Solution
A method involving multiple polishing processes, including chemical mechanical polishing, diamond mechanical polishing, and blasting media, is used to form and polish sapphire components, particularly for curved or non-planar surfaces, followed by annealing to enhance processing and fill in defects, and decorative ink application using pad printing and masking techniques to achieve a uniform finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sapphire is used to replace glass screens, then durability and resistance to damage are improved, but manufacturing difficulty increases due to sapphire's hardness
Solution Approach 1:
The polishing process is divided into multiple sequential stages: coarse polishing to remove defects, intermediate polishing to refine the surface, and fine polishing to achieve the final optical finish. Each stage uses progressively finer abrasives and optimized parameters, allowing the extremely hard sapphire material to be processed effectively by breaking down the complex manufacturing challenge into manageable steps.
Solution Approach 2:
The patent employs systematic parameter changes across different polishing stages, including varying abrasive particle size, polishing pressure, rotation speed, and slurry composition. These parameter adjustments enable effective material removal and surface finishing of sapphire despite its high hardness, transforming the manufacturing difficulty by adapting process parameters to match the material's properties.
2Ease of manufacture
If conventional polishing techniques are used on curved sapphire surfaces, then the process is simple, but the polish quality is inadequate
Solution Approach 1:
A specially designed polishing compound or slurry acts as an intermediary between the polishing tool and the curved sapphire surface. This intermediary material fills in the gaps and adapts to the curved geometry, enabling uniform material removal and consistent surface finish on complex curved surfaces that would be difficult to polish with direct mechanical contact alone.
Solution Approach 2:
The patent introduces additional process dimensions beyond simple mechanical polishing, such as chemical-mechanical polishing (CMP) that combines chemical etching with mechanical abrasion. This multi-dimensional approach allows simultaneous achievement of material removal, surface smoothing, and curvature conformity, producing high-quality finishes on complex geometries.
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 method effectively produces a sapphire cover with improved durability and aesthetic appeal by ensuring a polished and visually uniform finish on both planar and curved surfaces, enhancing the device's resistance to damage and user interaction.
Implementation Method 1
performing a second polishing process on the groove of the sapphire component using blasting media
Implementation Method 2
annealing the sapphire component
Data Source
AI summary
A cover for an electronic device and methods of forming a cover is disclosed. The electronic device may include a housing, and a cover coupled to the housing. The cover may have an inner surface having at least one of an intermediate polish and a final polish, a groove formed on the inner surface, and an outer surface positioned opposite the inner surface. The outer surface may have at least one of the intermediate polish and the final polish. The cover may also have a rounded perimeter portion formed between the inner surface and the outer surface. The rounded perimeter portion may be positioned adjacent the groove. The method for forming the cover may include performing a first polishing process on the sapphire component using a polishing tool, and performing a second polishing process on the groove of the sapphire component forming the cover using blasting media.