Backlighted Key Plunger with Diffusing Body
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Solution Overview
Problem
Conventional backlight systems in handheld electronic devices, such as PDAs and wireless telephones, suffer from dark spots due to internal components like stalks of plungers impeding light dispersion within keys, leading to inadequate illumination.
Innovation Solution
A key plunger design featuring a stalk made of a transparent material and a body section made of a translucent, light-diffusing material, where the two materials are combined using a two-shot moulding process or welding, allowing for improved light transmission and dispersion to reduce shadow regions within the key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional backlight system is used with internal components like stalks of plungers, then the key structure is functional and complete, but dark spots appear due to impeded light dispersion
Solution Approach 1:
The plunger is designed with different material properties in different regions: the stalk is made of transparent material for optimal light transmission, while the body section uses translucent light-diffusing material to eliminate dark spots. This local differentiation of material properties resolves the contradiction by optimizing each region's function while maintaining overall structural completeness.
Solution Approach 2:
The plunger combines transparent and translucent light-diffusing materials in a single component through two-shot molding or welding. This composite structure allows the stalk to transmit light effectively while the body section diffuses light uniformly, eliminating dark spots without requiring separate components and maintaining structural integrity.
2Illumination intensity
If transparent material is used for the stalk to improve light transmission, then light dispersion improves, but manufacturing complexity increases
Solution Approach 1:
The transparent stalk and translucent body section are merged into a single integrated plunger component through two-shot molding or welding. This combining approach maintains the light transmission benefits of transparent material in the stalk while integrating it with the light-diffusing body section, achieving uniform illumination without requiring multiple separate parts that would complicate assembly.
3Illumination intensity
If translucent light-diffusing material is used for the body section to reduce dark spots, then illumination uniformity improves, but light transmission intensity decreases
Solution Approach 1:
The body section uses translucent light-diffusing material specifically in the regions where dark spots occur, while the stalk maintains transparent material for efficient light transmission. This localized application of light-diffusing properties achieves illumination uniformity without unnecessarily reducing overall light transmission efficiency.
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 light distribution within the key, reducing dark spots and providing more uniform illumination, thereby improving the user experience by ensuring better visibility of key characters.
Implementation Method 1
the second material disperses light from a source located below the body section which enters the body section into a region in the body section immediately over the stalk to brighten a first shadow region
Implementation Method 2
the transparent material transmits light passing through the stalk from the source to brighten a second shadow region located on a side of the stalk which is opposite to the source
Data Source
AI summary
The disclosure relates to a key plunger and a key assembly for a key of an electronic device. The plunger comprises: a stalk made of a first material allowing light to pass through and a body section connected to the top of the plinth. In the plunger, the body section is made of a second material and shaped to fit snugly within an interior of a cap for the key and to extend horizontally about the stalk. The second material is a translucent, light-diffusing material; the first material allows more light to pass therethrough than the second material. The key assembly comprises: a key plunger; a key cap shaped to fit over the key plunger; and a backlight to illuminate an interior of the key cap. The backlight may be located underneath the key plunger and to a side of the stalk.