Light Guide Plate with Varying Particle Concentration for Uniform Luminance
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Solution Overview
Problem
Large-sized liquid crystal televisions face challenges with backlight units that are thick, costly, and suffer from uneven luminance and light use efficiency, particularly when using cold cathode tubes and reflectors, and existing solutions either increase weight or complexity, or fail to optimize light distribution for convex or bell-shaped brightness profiles.
Innovation Solution
A light guide plate with a rectangular light exit surface, multiple layers with varying particle concentrations of polydisperse scattering particles, and a concave shape to optimize light distribution, reducing thickness while maintaining high light use efficiency and minimizing luminance unevenness, featuring a two-layer structure with different particle concentrations and a specific cross-sectional shape to enhance light exit efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a light guide plate with varying thickness is used to reduce overall thickness, then the thickness is reduced, but luminance unevenness increases
Solution Approach 1:
The patent applies local quality by varying the particle concentration of scattering particles in different regions of the light guide plate. Specifically, the particle concentration is higher near the light incidence surface and lower toward the light exit surface, creating localized optical properties that compensate for the thickness variation and maintain uniform luminance distribution across the exit surface.
Solution Approach 2:
The patent changes the optical parameters of the light guide plate by varying the concentration of scattering particles in different regions. This parameter change allows the plate to maintain uniform light output despite having non-uniform thickness, as the scattering particle distribution compensates for the geometric variations.
2Illumination intensity
If scattering particles are incorporated to diffuse light uniformly, then luminance uniformity is improved, but light use efficiency decreases
Solution Approach 1:
The patent uses local quality by concentrating scattering particles in specific regions (higher concentration near the incidence surface) rather than distributing them uniformly throughout the plate. This localized approach provides sufficient light diffusion where needed while minimizing unnecessary scattering in other regions, thereby improving light use efficiency.
Solution Approach 2:
The patent applies partial action by using scattering particles only in certain regions of the light guide plate rather than throughout the entire structure. The varying concentration distribution ensures adequate light diffusion in critical areas while reducing the total amount of scattering material, thus balancing luminance uniformity with light use efficiency.
3Illumination intensity
If cold cathode tubes and reflectors are used to ensure uniform light distribution, then luminance uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for separate reflector components by incorporating the light-diffusing function directly into the light guide plate through varying particle concentration. This integration removes unnecessary components, simplifies the overall structure, and reduces cost while maintaining luminance uniformity.
Solution Approach 2:
The light guide plate performs multiple functions: it guides light from the incidence surface to the exit surface, diffuses light uniformly through varying particle concentration, and compensates for thickness variations. This multi-functionality eliminates the need for separate reflectors and diffusion elements, reducing device complexity.
4Ease of manufacture
If a thicker light guide plate is used to maintain structural integrity and light distribution, then manufacturing ease is improved, but weight increases
Solution Approach 1:
The patent changes the optical parameters (particle concentration distribution) to compensate for reduced thickness, allowing the light guide plate to be thinner while maintaining both structural integrity and light distribution performance. This enables weight reduction without sacrificing manufacturing feasibility.
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 enables a thin, high-efficiency light guide plate with reduced unevenness in luminance and weight, achieving a convex or bell-shaped brightness distribution, allowing for thinner designs and lower costs while maintaining effective light use and distribution.
Implementation Method 1
scattering particles being dispersed in the light guide plate
Data Source
AI summary
The light guide plate has at least two layers which are superposed on each other in the direction almost perpendicular to the light exit surface and contain the scattering particles at different particle concentrations, the scattering particles are polydisperse particles including a mixture of particles with different particle sizes, and the combined particle concentrations in each portion of the light guide plate is different by changing the thicknesses of the first layer and the second layer in the direction almost perpendicular to the exit surface.