Deflection Web with Varying Thickness Flanges for Keypad Assembly
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Solution Overview
Problem
Keypad assemblies in mobile communications devices face challenges in providing effective protection against water and contaminants while maintaining key positioning and depression guidance, and in achieving optimal tactile feedback and light shielding without compromising the structural integrity and functionality of the keypad.
Innovation Solution
A keypad assembly featuring a deflection web with radially outwardly extending flanges of varying thickness, anchored to a keypad base, which exerts a pre-load force on actuators to counteract key depression and includes a light shielding layer to reduce light leakage and enhance tactile feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a deflection web is used to protect against water and contaminants, then protection effectiveness is improved, but key positioning precision and depression guidance may deteriorate
Solution Approach 1:
The deflection web incorporates localized thickened flanges around each actuator that provide precise positioning features. These flanges have varying thicknesses (e.g., 0.5mm to 2mm) that create specific geometric profiles for key alignment, while the rest of the web maintains flexibility for contaminant protection. This local differentiation resolves the contradiction between protection and precision.
Solution Approach 2:
The deflection web is segmented into multiple functional zones: protective membrane areas for contaminant barrier, thickened flange regions for key positioning, and actuator coupling zones for force transmission. This segmentation allows each zone to optimize its specific function without compromising overall performance.
2Ease of operation
If a deflection web with varying thickness flange is used to exert pre-load force on actuators, then tactile feedback is improved, but device complexity increases
Solution Approach 1:
The deflection web merges multiple functions into a single integrated component: it combines the protective membrane, the positioning flanges, and the pre-load spring elements into one piece. The varying thickness flanges simultaneously provide structural support, positioning guidance, and elastic pre-load force, eliminating the need for separate components and reducing overall device complexity despite the enhanced tactile feedback functionality.
3Force
If the flange thickness varies radially outward from the actuator, then pre-load force on the actuator is improved, but manufacturing precision requirements increase
Solution Approach 1:
The flange thickness is deliberately varied as a gradient parameter rather than a constant dimension. By transitioning from thinner inner regions (closer to actuators) to thicker outer regions, the design optimizes stress distribution and pre-load force generation. This parameter change approach allows for more forgiving manufacturing tolerances compared to maintaining uniform thin dimensions throughout.
4Illumination intensity
If a light shielding layer is added to reduce light leakage, then light shielding effectiveness is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The light shielding layer is merged with the deflection web structure, either as an integrated layer during co-molding or as a closely coupled component. This integration eliminates the need for separate assembly steps and reduces the overall component count, thereby minimizing the increase in device complexity while achieving effective light shielding to prevent backlight leakage around keys.
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 protects against contaminants, provides precise key positioning, and enhances tactile feedback while maintaining the structural integrity and functionality of the keypad, ensuring reliable operation and user experience.
Implementation Method 1
a flexible membrane resiliently coupling the plurality of actuators together
Implementation Method 2
when a key is in a first undepressed position, the corresponding flange exerts a pre-load force on the corresponding actuator
Data Source
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AI summary
A deflection web is provided for use in a keypad assembly. The deflection web comprises a plurality of actuators resiliently coupled together by a flexible membrane. Each actuator of the deflection web corresponds to a key of the keypad assembly, and for each actuator, the flexible membrane comprises a corresponding radially outwardly extending flange whose thickness varies in a direction from the corresponding actuator. In some instances, the thickness of the flange may increase as the flange extends a distance radially outward from its corresponding actuator. A method for creating the deflection web of the keypad assembly and a method for assembling the keypad assembly are also provided.