Keypad Assembly Light Guide Plate Uniform Illumination
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Solution Overview
Problem
Conventional keypad assemblies for electronic devices suffer from non-uniform illumination of key buttons, increased power consumption, and higher manufacturing costs due to the use of multiple LEDs, which also limit the ability to separately illuminate numbers and characters with different colors.
Innovation Solution
Incorporating a light guide plate with reflecting patterns and at least one optical filtering layer made of phosphor under each key button, which changes color in response to light wavelengths from multiple light emitting devices, allowing for separate and distinct color illumination of numbers, characters, and special characters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are installed to uniformly illuminate key buttons, then illumination uniformity is improved, but power consumption increases
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the LED and key buttons. The light guide plate receives light from a single LED and distributes it uniformly across the key button area through optical guiding and reflecting patterns, eliminating the need for multiple LEDs while maintaining uniform illumination.
Solution Approach 2:
The light guide plate serves multiple functions: it guides light from the LED, distributes light uniformly across the key buttons, and reflects light back toward the buttons through patterns on its bottom surface. This multi-functional component replaces what would otherwise require multiple separate LED sources.
2Illumination intensity
If multiple LEDs are installed to illuminate key buttons, then illumination coverage is improved, but manufacturing cost increases
Solution Approach 1:
Multiple light-emitting functions are merged into a single LED source. The light guide plate combines light guidance, distribution, and reflection functions into one component, reducing the total number of parts and simplifying the manufacturing process while achieving comprehensive illumination coverage.
Solution Approach 2:
The light guide plate acts as an intermediary that amplifies the utility of a single LED by distributing its light output across multiple key buttons, achieving the same illumination coverage that would otherwise require multiple LEDs, thereby reducing manufacturing cost.
3Adaptability or versatility
If optical filtering layers are added to enable color differentiation, then key button utility is improved, but device complexity increases
Solution Approach 1:
Different regions of the light guide plate are assigned different optical filtering layers with specific wavelength-selective properties. Each local region filters light differently to produce distinct colors for numbers, characters, and special characters, enabling enhanced key button utility through localized optical properties.
Solution Approach 2:
Optical filtering layers are applied to the light guide plate that selectively transmit or block different wavelengths of light. These layers change the color of the emitted light based on the underlying LED wavelength, enabling color differentiation for different key button elements without requiring separate LED sources for each color.
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
This solution enables improved key button utility by allowing numbers and characters to be illuminated with different colors, reducing power consumption and manufacturing complexity, while maintaining uniform illumination across all key buttons.
Implementation Method 1
at least one optical filtering layer whose color is changed into other colors by reacting or not reacting to the wavelengths of lights generated from the light emitting devices
Implementation Method 2
optical filtering layer made of phosphor
Implementation Method 3
a plurality of reflecting patterns on the bottom surface of the light guide plate for reflecting the light moving through the light guide plate toward the key buttons
Data Source
AI summary
A keypad assembly for an electronic device is disclosed. The keypad assembly includes a light guide plate through which a light moves, a plurality of first key buttons on the top surface of the light guide plate, a plurality of reflecting patterns on the bottom surface of the light guide plate for reflecting the light moving through the light guide plate toward the first key buttons, protrusions under the reflecting patterns, a plurality of light emitting devices for supplying the light to the light guide plate, and a switch board including a plurality of dome switches and at least one first optical filtering layer whose color is changed into various colors by reacting or not reacting to the wavelengths of lights generated from the light emitting devices is included under each of the first key buttons.