Backlight Keyswitch Light Mixing Structure for Uniform Symbol Color
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Solution Overview
Problem
Conventional backlight keyswitch designs using RGB LEDs often suffer from color shift issues due to varying mixing distances between red, green, and blue LED chips, leading to non-uniform lighting and visual effects.
Innovation Solution
The design incorporates ink layers and adhesive layers to adjust and scatter color lights, with ink layers filtering specific color lights and adhesive layers creating gaps to redirect light, ensuring uniform illumination by eliminating color shifts near LED chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If RGB LEDs with red, green, and blue LED chips arranged side by side are used, then the lighting function is provided, but color shift problem occurs in the symbol lighting effect
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the RGB LED chips and the symbol. The light guide plate includes a first light mixing region where red, green, and blue lights are mixed before reaching the symbol, and a second light mixing region where further mixing occurs. This intermediary structure ensures uniform color distribution across the symbol, eliminating the color shift problem that would otherwise occur due to the side-by-side arrangement of different colored LED chips.
Solution Approach 2:
The patent transitions from a two-dimensional side-by-side arrangement of LED chips to a three-dimensional light mixing structure. By stacking multiple light mixing regions vertically within the light guide plate, the patent creates additional mixing paths and extends the light interaction in the vertical dimension, enabling more thorough color mixing before the light reaches the symbol.
2Illumination intensity
If different mixing distances between red, green, and blue LED chips and symbol are used, then the lighting function is achieved, but lighting uniformity is affected
Solution Approach 1:
The patent applies different structural characteristics to different regions of the light guide plate. The first light mixing region has a first refractive index and the second light mixing region has a second refractive index, creating local variations in optical properties. Additionally, the light guide plate includes specific light entering and exiting surfaces with tailored geometries. These local quality variations enable precise control over light propagation paths and mixing distances for different colors, ensuring uniform lighting across the symbol.
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 approach enhances lighting uniformity and visual effect by eliminating color shifts, resulting in improved backlight keyswitch performance.
Implementation Method 1
ink layers to partially adjusting color lights of lighting units
Implementation Method 2
adhesive layers to scatter the color lights of the lighting units
Data Source
AI summary
A backlight keyswitch includes a cap with a symbol, and a backlight module under the cap and having first and second light modifying layers, a light guide plate, a light-blocking sheet having a transparent region corresponding to the cap, and first, third, and second lighting units arranged sequentially along a longitudinal direction for emitting first, third, and second color lights. The first and second light modifying layers might be ink layers formed on the light-blocking sheet and located outside the first and second lighting units, with colors of the first and second ink layers at least corresponding to colors of the second and first color lights respectively to achieve a mixed color. Alternatively, the first and second light modifying layers might be adhesive layers arrange parallel to the light guide plate, the first and second adhesive layers scattering a respective one of the first and second color light.