Light Modulator Layer for Edge-Lit Backlight Luminance Uniformity
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Solution Overview
Problem
Existing edge light type backlight systems for liquid crystal displays face challenges in achieving a high modulation ratio while maintaining uniform luminance across a plane, as they struggle to partially modulate light intensity effectively.
Innovation Solution
A light modulator layer with a first region that changes between transparent and scatterable states based on an electric field intensity and a second region that remains more transparent at a certain electric field intensity is integrated into the light guide plate, with an increased occupancy rate of the first region as distance from the light source increases, allowing for controlled luminance adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light modulator with uniform light extraction pattern is used to make luminance uniform in a plane, then luminance uniformity is improved, but luminance in dark display is increased, resulting in reduced modulation ratio
Solution Approach 1:
The patent applies local quality by creating a light modulator layer with spatially varying properties. The occupancy rate of the first region (scatterable state) is increased with distance from the light source, while the second region (more transparent state) has lower occupancy rate near the light source. This non-uniform distribution allows different regions to contribute differently to luminance control, achieving both luminance uniformity and high modulation ratio by locally optimizing the balance between light extraction and light blocking.
2Illumination intensity
If the occupancy rate of the first region is increased with distance from the light source, then luminance uniformity is achieved, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by varying the occupancy rate of the first and second regions as a function of distance from the light source. Specifically, the occupancy rate of the first region increases with distance, while the occupancy rate of the second region decreases with distance. This continuous parameter variation allows the system to adapt to the non-uniform light distribution from the edge light source, achieving luminance uniformity through a systematic gradient rather than complex discrete structures.
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 configuration enhances the modulation ratio by reducing luminance in the transparent region and increasing it in the scattering region, resulting in improved luminance uniformity and increased partial white-display luminance without increasing input power.
Implementation Method 1
a light modulator layer (34), which includes a first region (34A) being changed between a transparent state and a scatterable state depending on intensity of an electric field
Implementation Method 2
a light guide plate (10), a light source (20) disposed on a side face of the light guide plate (10)
Data Source
AI summary
An illumination device is provided and has a light guide plate, a light source and a light modulator, wherein the light modulator has a pair of transparent substrates a pair of electrodes and a light modulator layer. The light modulator layer includes a first region being changed between a transparent state and a scatterable state depending on intensity of an electric field, and a second region being more transparent than the first region in a scatterable state at an electric field having a certain intensity, the electric field being applied when the first region is changed between the transparent state and the scatterable state, and an occupancy rate of the first region in the light modulator layer is increased with increase in distance from the light source.