Light Guide Plate Prisms and Condensing Lenses Brightness Uniformity
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Solution Overview
Problem
Conventional light guide plates in side-emitting backlight modules suffer from non-uniform brightness due to the concentration of light by prisms, leading to bright and dark areas, which is exacerbated by the use of line or point light sources, and existing solutions like fogging the thick end-surface increase fabrication complexity and cost.
Innovation Solution
A light guide plate with a micro-structure featuring a transparent substrate, prisms, and condensing lenses arranged between them, where the lenses are distributed sparsely to densely along the crest line of the prisms to control light distribution and enhance uniformity, with the option of integrative design and varying shapes such as columns, truncated cones, or spherical surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If prisms are used to gather light in the light guide plate, then light concentration ability is improved, but brightness uniformity deteriorates due to obvious bright and dark areas
Solution Approach 1:
The patent applies local quality by making different regions of the light guide plate have different properties. The bottom surface is divided into multiple regions with varying prism densities, and condensing lenses are selectively positioned in specific regions. This creates local variations in light gathering capability that compensate for the non-uniform light distribution from line or point light sources, thereby improving overall brightness uniformity while maintaining light concentration ability.
Solution Approach 2:
The patent segments the light guide plate's bottom surface into multiple regions with different prism arrangements. Instead of using uniform prisms throughout, the prisms are distributed with varying densities across different zones. This segmentation allows each region to be optimized for its specific function - some regions focus on light gathering while others prioritize uniformity, resolving the contradiction between concentration and uniformity.
2Stability of the object's composition
If fogging surface is fabricated on the thick end-surface to scatter light, then brightness uniformity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple functions into the existing prism structure on the bottom surface. Instead of adding a separate fogging layer or treatment to the thick end-surface, the invention integrates light scattering and uniformity control directly into the prism arrangement and condensing lens positioning. This combination eliminates the need for additional fabrication steps while achieving the desired brightness uniformity.
Solution Approach 2:
The patent uses the existing prism micro-structure as a template and modifies its distribution pattern rather than creating an entirely new fogging surface. By copying and adapting the proven prism concept with varied density arrangements and adding condensing lenses, the invention achieves uniformity improvement without the complexity of fabricating a separate fogged surface layer.
3Use of energy by moving object
If condensing lenses are densely distributed to improve light gathering, then light use efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by varying the density of condensing lenses across different regions of the light guide plate. Instead of uniform dense distribution throughout, lenses are concentrated in regions where they are most needed to compensate for light source non-uniformity, while other regions have fewer or no lenses. This localized approach maintains light gathering efficiency while reducing overall manufacturing precision requirements.
Solution Approach 2:
The patent uses partial action by positioning condensing lenses only in specific regions rather than uniformly across the entire light guide plate. This selective placement provides sufficient light gathering enhancement in critical areas without requiring precise lens positioning everywhere, thereby maintaining light use efficiency while lowering manufacturing precision demands.
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 improves light gathering and distribution, increasing brightness uniformity and efficiency while reducing fabrication complexity and costs by adjusting the density of condensing lenses to match the light source's intensity profile.
Implementation Method 1
Most of the light is transferred to the thin end-surface 124 by total reflection after it enters the light guide plate 120. When the light is transferred to the prisms 126a on the bottom surface 126 of the light guide plate 120, it is concentrated and then emitted out from the top surface 128
Implementation Method 2
The plural condensing lenses are disposed between the two adjacent prisms, and distributed from sparsely to densely along a direction of a crest line of each of the prisms
Data Source
AI summary
A light guide plate and a side-emitting backlight module having the same are disclosed. The light guide plate includes a transparent substrate, a plurality of prisms and a plurality of condensing lenses. The prisms are arranged side by side on one surface of the transparent substrate. The condensing lenses are disposed between two adjacent prisms, and distributed from sparsely to densely along a direction of a crest line of each of the prisms.