Light Guide Plate High Density Regions for Backlight Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light guide plates (LGP) in edge-lit backlight units suffer from hotspots due to triangular dark regions between neighboring LEDs, which affect picture quality, and existing solutions either increase cost or are difficult to implement effectively.
Innovation Solution
A light guide plate with low and high density regions, where high density regions made of polycarbonate are strategically placed in the triangular dark areas between LEDs, and the low density regions are made of polymethylmethacrylate, using a core-pulling injection molding method to optimize the distribution of materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pitch between two neighboring LEDs is decreased to reduce the triangular dark region, then the dark region area is reduced, but more LEDs are needed which increases the cost
Solution Approach 1:
The patent applies local quality by creating high density regions with different material composition (polycarbonate and PMMA mixture) specifically in the triangular dark regions between LEDs, while the rest of the light guide plate maintains uniform material composition. This localized modification targets the dark region brightness issue without requiring changes to the overall LED arrangement or adding more LEDs, thus resolving the contradiction between reducing dark region area and avoiding increased LED quantity/cost.
2Object-affected harmful factors
If the brightness of the dark region is adjusted through designing the pattern of the LGP to mitigate hotspots, then the hotspot phenomenon is alleviated, but it is difficult to realize
Solution Approach 1:
The patent changes the material composition parameter in the triangular dark regions by mixing polycarbonate and PMMA to create high density regions with specific optical properties. This parameter change (material composition) provides a controllable and manufacturable approach to adjust dark region brightness and mitigate hotspots, avoiding the complexity of intricate pattern design while achieving the desired optical effect through material science.
3Object-affected harmful factors
If the existing film material is replaced with a better film material to solve the hotspot phenomenon, then the hotspot issue is resolved, but the cost increases
Solution Approach 1:
Instead of replacing the entire light guide plate material with a more expensive alternative, the patent applies local quality by using a mixed material composition (polycarbonate and PMMA) only in the triangular dark regions. This localized approach achieves hotspot mitigation with minimal material cost increase, as the majority of the light guide plate retains the original PMMA material while only specific regions use the enhanced composite material.
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 design enhances light distribution in the dark regions, reducing hotspots and achieving uniform brightness without compromising light efficiency, thereby improving the overall performance of the backlight unit.
Implementation Method 1
The high density regions are made of polycarbonate and the low density region is made of polymethylmethacrylate. As light enters the light guide plate, the different density regions cause light refraction and redistribution, enhancing light distribution in the dark regions.
Data Source
Figure 1~2
Figure 3~4
AI summary
Embodiments of the invention relate to a light guide plate, a method for fabricating the same and a backlight unit. The light guide plate comprises a low density region (4) and a plurality of high density regions (5), wherein the plurality of high density regions (5) are separately disposed on a light incident side of the light guide plate. The high density regions (5) are located in the region of light guide plate corresponding to a region (6) between two separate neighboring dot light sources, when a plurality of separate dot light sources are used as a side light source. The high density regions (5) are located in a triangular dark region on the light guide plate generated by two neighboring separate dot light sources.