Transparent Button Masking Layer UV Discoloration Prevention
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Solution Overview
Problem
Transparent masking layers in electronic devices, such as those containing titanium oxide particles, tend to discolor when exposed to ultraviolet light, leading to unwanted color changes like a bluish tint.
Innovation Solution
A white opaque masking layer is formed using inorganic materials deposited via physical vapor deposition, followed by an annealing process in the presence of oxygen to create a porous structure that scatters light, and an additional optically dense metal oxide layer is applied to enhance optical density, preventing discoloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If white ink layers containing titanium oxide particles are used to coat transparent structures, then the masking layer provides adequate opacity and white color, but the layer discolors and acquires a bluish tint when exposed to ultraviolet light
Solution Approach 1:
The patent applies composite materials by combining multiple inorganic layers with different properties: a first inorganic layer (e.g., silicon oxide) providing base opacity and UV resistance, and a second inorganic layer (e.g., titanium oxide) providing enhanced white color and scattering. This composite structure maintains the benefits of titanium oxide while adding UV stability through the silicon oxide layer, preventing bluish discoloration under UV exposure.
Solution Approach 2:
The patent changes the material composition parameters by replacing organic ink with inorganic materials and adjusting the layer structure. By modifying the chemical composition from organic-based ink containing titanium oxide particles to inorganic layers such as silicon oxide and titanium oxide, the masking layer achieves improved UV resistance and color stability while maintaining adequate opacity.
2Ease of manufacture
If organic masking materials are used to coat transparent structures, then the coating process is simple and cost-effective, but the masking material is prone to discoloration under UV light
Solution Approach 1:
The patent substitutes the organic coating system with an inorganic deposition system. Instead of using organic ink that can be applied through simple coating processes, the patent employs physical vapor deposition or chemical vapor deposition to deposit inorganic layers. This substitution eliminates the discoloration issue while maintaining manufacturing feasibility through established deposition techniques.
Solution Approach 2:
The patent changes the material type parameter from organic to inorganic, fundamentally altering the masking layer composition. By transitioning from organic masking materials to inorganic layers (silicon oxide, titanium oxide), the system maintains ease of manufacture through deposition processes while achieving superior color stability and UV resistance.
3Productivity
If a single-layer masking structure is used, then the manufacturing process is simple and quick, but the optical density may be insufficient to prevent discoloration
Solution Approach 1:
The patent segments the masking layer into multiple distinct inorganic layers, each serving a specific function. The first inorganic layer (e.g., silicon oxide) provides base opacity and UV resistance, while the second inorganic layer (e.g., titanium oxide) enhances white color and light scattering. This segmentation allows each layer to be optimized for its specific function, achieving sufficient optical density while maintaining manufacturing efficiency through sequential deposition.
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 effectively maintains the white color of the masking layer even under UV exposure, ensuring the optical density and performance of components like fingerprint sensors are preserved.
Implementation Method 1
The opaque masking layer may include a white porous inorganic layer. The opaque masking layer may also have an opaque layer that covers the white porous inorganic layer to increase the optical density of the opaque masking layer.
Implementation Method 2
followed by an annealing process in the presence of oxygen to form a porous layer that scatters light
Implementation Method 3
form a porous layer that scatters light
Implementation Method 4
an additional optically dense metal oxide layer is applied to enhance optical density, preventing discoloration
Data Source
AI summary
An electronic device may have transparent structures. The transparent structures may include a transparent member such as a transparent button member. The transparent member may have an inner surface that is covered with an opaque masking layer. The opaque masking layer may be white and may include a white porous inorganic layer covered with an opaque layer that increases the optical density of the opaque masking layer. The white porous inorganic layer may be formed by depositing a metal or other material using physical vapor deposition followed by an annealing process in the presence of oxygen. The opaque layer may be an optically dense inorganic layer such as a metal oxide layer. The button member may be located within an opening in a display cover layer. A fingerprint sensor may be attached to the opaque layer on the button member.