Parabolic Light Guide for Display Illumination
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Solution Overview
Problem
Current front-light lighting systems for display devices face challenges in achieving high lighting efficiency without interfering with readability, and they have inefficient power consumption and high costs, making them unsuitable for industrial manufacturing, especially in portable devices where energy reserves are limited.
Innovation Solution
A lighting system with a light guide featuring a parabolic injection and collimation zone, where the light source is placed opposite the top of the parabola, ensuring high injection efficiency and uniform luminous flux distribution, along with a planar extraction zone for optimal light distribution, simplifying the orientation of light extractors and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide with extractors is used for front-light illumination, then the light can be extracted towards the display device, but the extractors interfere with the readability of the information displayed
Solution Approach 1:
The patent introduces a reflective layer as an intermediary element positioned between the light guide and the display device. This reflective layer redirects the extracted light away from the viewer's line of sight while maintaining illumination on the display surface, thereby eliminating readability interference caused by direct extractor visibility
Solution Approach 2:
The patent changes the spatial dimension of light extraction by using a reflective layer to redirect light at different angles. Instead of extracting light directly toward the viewer (2D plane extraction), the system uses the reflective layer to redirect light in a third dimension (angular redirection), separating the illumination function from the viewing function
2Illumination intensity
If conventional front-light lighting systems are used, then illumination is provided, but the power consumption is high and efficiency is low
Solution Approach 1:
The patent replaces conventional high-power illumination systems with a more efficient light guide-based system. By using total internal reflection and controlled extraction mechanisms, the system achieves better illumination quality with lower power consumption, substituting inefficient mechanical lighting approaches with optimized optical pathways
Solution Approach 2:
The patent optimizes multiple parameters including the refractive index of the light guide material, the geometry and distribution of extractors, and the positioning of the reflective layer. These parameter changes collectively improve light extraction efficiency while reducing the overall power required for illumination
3Illumination intensity
If the light source is directly visible, then illumination is provided, but 'hot spots' appear and uniformity is reduced
Solution Approach 1:
The reflective layer serves as an intermediary that diffuses and redistributes the light from the source. By positioning this reflective layer strategically, the system maintains high light output while achieving uniform illumination across the display surface, eliminating hot spots that would otherwise be visible
Solution Approach 2:
The patent implements non-uniform distribution of light extractors along the light guide, with higher extractor density in regions requiring more illumination and lower density in regions requiring less. This local optimization of extractor distribution, combined with the reflective layer, achieves uniform overall illumination while maintaining high light output
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 system achieves excellent light injection efficiency, high collimation, and uniform illumination, optimizing the power-to-light ratio and simplifying manufacturing, while hiding the light source from view to prevent 'hot spots', resulting in a compact and efficient lighting solution.
Implementation Method 1
a planar section for injecting and collimating light of parabolic shape
Implementation Method 2
The light guide comprises at least one planar section for injecting and collimating light of parabolic shape followed by a planar section for extracting light of constant rectangular section
Implementation Method 3
followed by a planar section for extracting light of constant rectangular section
Data Source
Figure 1~3
Figure 4A~6B
Figure 6C~7B
AI summary
Lighting system of an information display device (56), this lighting system comprising a light guide (30) into which the light produced by a light source (38) is injected, this lighting system being characterized in that the light guide (30) comprises a flat light injection and collimation zone (32) in the shape of a parabola, this parabola comprising two branches (48a, 48b) connected to each other by a vertex (40), the light source (38) being disposed opposite the vertex (40), the branches (48a, 48b) of the parabola which delimit the contour of the flat injection and collimation zone (32) being extended by a flat light extraction zone (36) propagating inside the guide (30), this extraction zone (36) being of rectangular cross-section and being provided with light extractors (54).