Backlight Unit Diffuser Plate with Dual Haze Layers for Side Lobe Control
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Solution Overview
Problem
Backlight units for liquid crystal display devices suffer from light efficiency and viewing angle issues due to side lobes, which result in non-uniform brightness and reduced image quality.
Innovation Solution
A backlight unit design incorporating a diffuser plate with a diffusion layer and a light-concentrating layer featuring dome-shaped lenticular lenses, along with a reflective polarizing sheet, to minimize side lobes and enhance light concentration and viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional diffuser plate is used, then light diffusion is achieved, but side lobes cause non-uniform brightness and reduced viewing angles
Solution Approach 1:
The diffuser plate is divided into multiple diffusion layers with different haze values (first diffusion layer with 70-90% haze, second diffusion layer with 40-60% haze). This segmentation allows each layer to perform a specific function: the first layer provides strong diffusion to eliminate side lobes, while the second layer maintains brightness uniformity, thereby resolving the contradiction between brightness uniformity and side lobe elimination.
Solution Approach 2:
Different regions of the optical system are assigned different diffusion properties. The first diffusion layer uses high haze material for aggressive side lobe suppression, while the second diffusion layer uses medium haze material for brightness uniformity. This local differentiation of optical properties allows simultaneous achievement of uniform brightness and side lobe reduction.
2Object-affected harmful factors
If light diffusion is increased to reduce side lobes, then viewing angles improve, but light efficiency decreases
Solution Approach 1:
The diffusion function is segmented across two layers with different haze values. The first layer (70-90% haze) handles the heavy lifting of side lobe suppression and viewing angle expansion, while the second layer (40-60% haze) provides mild diffusion to maintain uniformity without excessive light scattering. This segmentation optimizes the balance between viewing angle improvement and light efficiency preservation.
Solution Approach 2:
The haze parameter is strategically varied across different diffusion layers. By using high haze (70-90%) in the first layer and medium haze (40-60%) in the second layer, the system achieves optimal light diffusion for viewing angle expansion while minimizing unnecessary light scattering that would reduce efficiency. The reflective polarizing sheet with 60-90% haze further optimizes this parameter distribution.
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 significantly improves light efficiency and viewing angles, ensuring uniform brightness and high-quality image display by effectively redirecting and concentrating light, thereby reducing light leakage and enhancing display performance.
Implementation Method 1
a diffusion layer at a first surface of the base plate facing the at least one lamp
Implementation Method 2
a light concentrating layer at a second surface of the base plate opposite to the first surface
Implementation Method 3
a reflection sheet, at least one lamp arranged over the reflection sheet
Data Source
AI summary
A backlight unit for a liquid crystal display device includes a reflection sheet, at least one lamp arranged over the reflection sheet, a diffuser plate over the at least one lamp, the diffuser plate including a base plate of a transparent material, a diffusion layer at a first surface of the base plate facing the at least one lamp, and a light concentrating layer at a second surface of the base plate opposite to the first surface and formed of a same material as the base plate, and optical sheets over the diffuser plate.