Backlight Key Plunger with Translucent Body for Shadow Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional backlight systems for keypads in handheld electronic devices suffer from light dispersion issues due to internal components, resulting in dark spots where light leaves the keys, which affects visibility and user experience.
Innovation Solution
A key assembly with a translucent, light-diffusing key plunger and a transparent stalk made of materials like clear polycarbonate or resin, which reduces shadows by allowing light to pass through and dispersing it within the key cap, combined with a two-shot moulding process for the plinth and body section to enhance light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional backlight system is used with internal components (stalks, plungers), then the key assembly provides structural support and functionality, but light dispersion is impeded creating dark spots on the key surface
Solution Approach 1:
The key plunger is designed with non-uniform optical properties: the upper portion is made of translucent material for light diffusion, while the lower stalk portion is made of transparent material for light transmission. This local differentiation allows each region to perform its specific function optimally without compromising overall light dispersion.
Solution Approach 2:
The patent changes the optical parameters (translucency, transparency) of different portions of the key plunger to optimize light dispersion. The translucent upper portion diffuses light to eliminate dark spots, while the transparent lower portion allows light to pass through to activate the switch mechanism.
2Illumination intensity
If a translucent, light-diffusing material is used for the key plunger body section, then light dispersion is improved and dark spots are reduced, but manufacturing complexity increases
Solution Approach 1:
The key plunger is constructed as a composite structure combining translucent material for the upper body section and transparent material for the lower stalk. This composite approach allows optimization of light dispersion in the upper portion while maintaining structural functionality in the lower portion, achieving both performance and manufacturability.
Solution Approach 2:
The key plunger is segmented into distinct portions (upper body section and lower stalk) with different material properties. This segmentation allows each portion to be optimized for its specific function: light diffusion above and light transmission below, while simplifying the manufacturing process by treating them as separate components.
3Illumination intensity
If a transparent stalk material is used, then light can pass through reducing shadows, but the structural strength may be compromised
Solution Approach 1:
The stalk is designed with transparent material specifically in the regions where light transmission is critical, while maintaining sufficient structural thickness and geometry to provide the necessary mechanical strength for switch activation. The local optimization of material properties balances optical and mechanical requirements.
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 improves light dispersion and reduces shadows within the key assembly, providing better illumination and visibility of key symbols, enhancing the user experience by ensuring consistent backlighting across the keypad.
Implementation Method 1
a body section made of a translucent, light-diffusing material... which assists in reducing said shadow in said region in said body section immediately above said stalk by dispersing light within said body section about said region
Implementation Method 2
the stalk being made of a transparent material allowing light to pass through
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a key assembly for a key of a keypad of an electronic device. The assembly comprises: a key cap for the key having at least one light transmitting region in its top; and a key plunger for the key. The plunger comprises: a stalk made of a transparent material allowing light to pass through; a plinth connected to the top of the stalk; and a body section connected to the top of the plinth made of a translucent, light-diffusing material. The body section is shaped to fit snugly within an interior of a cap for the key.