Light Guide Plate Illuminance Uniformity Design
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Solution Overview
Problem
Current light guide plates in direct-type backlight modules do not provide uniform light output due to inadequate distribution of scattering dots, leading to reduced illuminance uniformity in LCDs.
Innovation Solution
A method is developed to design and manufacture light guide plates by dividing the light input surface into concentric annuluses based on illuminance distribution, determining the effective density and number of scattering dots, and randomly distributing them to achieve improved uniformity, using formulas to calculate radii and densities, and employing random distribution to eliminate Moiré patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If scattering dots are distributed on the light guide plate surface, then light scattering function is provided, but illuminance uniformity deteriorates due to inadequate distribution
Solution Approach 1:
The light guide plate surface is segmented into multiple concentric annular regions, with each region having independently optimized scattering dot density. This segmentation allows different areas to have tailored dot distributions that collectively achieve uniform illuminance across the entire surface.
Solution Approach 2:
Different regions of the light guide plate are assigned different scattering dot densities according to their specific illuminance requirements. The dot density varies locally across the surface, with higher densities in regions requiring more scattering and lower densities in regions that already have sufficient illumination.
2Ease of manufacture
If conventional scattering dot distribution is used, then manufacturing is simple, but Moiré patterns are generated reducing visual quality
Solution Approach 1:
The scattering dots are arranged in an asymmetric concentric annular pattern rather than a regular grid or symmetric pattern. This asymmetric distribution disrupts the periodicity that causes Moiré effects while maintaining manufacturing feasibility through standardized dot placement within each annular region.
3Productivity
If scattering dot density is increased, then light scattering efficiency improves, but illuminance uniformity deteriorates due to over-saturation in certain areas
Solution Approach 1:
The scattering dot distribution is segmented into multiple annular zones with progressively varying densities. This prevents any single area from becoming over-saturated with dots while ensuring sufficient scattering efficiency is achieved across the entire light guide plate surface.
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 method significantly enhances illuminance uniformity to 91% and eliminates Moiré patterns, improving the efficiency and performance of direct-type backlight modules.
Implementation Method 1
The light guide plate for a direct-type backlight module according to a related art includes a top surface, a light input surface opposite to the top surface, and at least one side connecting the light input surface and the top surface. At least one of the light input surface and the top surface includes a plurality of scattering dots.
Data Source
AI summary
A method for designing a light guide plate includes the following steps. A raw light guide plate having a light input surface and a light output surface is provided. A region of the light input surface is divided into several annuluses according to a luminance distribution E(ρ,θ) of the light output surface. A scattering dots density D(ρ,θ) of each annulus on the light input surface is figured out. A total number N of the scattering dots of each annulus on the light input surface are gained, and the scattering dots is randomly distributed in the each annulus defined on the light input surface, whereby a designed light guide plate is obtained.