Anisotropic Diffusion Sheet for LCD Backlight Luminance Control
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Solution Overview
Problem
Conventional isotropic diffusion sheets used in liquid crystal display devices reduce luminance in certain directions excessively and are costly to produce due to complex processes like orientation, making them inefficient and expensive.
Innovation Solution
An anisotropic diffusion sheet comprising an isotropic diffusion layer and a reflector with inclined surfaces that isotropically diffuse light and then anisotropically reflect it, providing different vertical and horizontal luminance distributions, thereby improving light efficiency and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional isotropic diffusion sheets are used to diffuse light, then light scattering is achieved, but luminance is reduced excessively in certain directions and production cost increases due to complex orientation processes
Solution Approach 1:
The diffusion sheet is segmented into multiple functional layers: an isotropic diffusion layer for uniform light scattering and a prism layer with specific refractive indices for directional light control. This segmentation allows each layer to perform its specialized function independently, achieving anisotropic luminance distribution without complex orientation processes
Solution Approach 2:
Different regions of the diffusion sheet have different optical properties. The isotropic diffusion layer has uniform scattering properties in all directions, while the prism layer has direction-dependent refractive indices that control light propagation differently in vertical versus horizontal directions, creating local quality variations for optimized luminance distribution
2Illumination intensity
If conventional anisotropic light scattering films with dispersed particles are used, then high anisotropicity is achieved, but production cost increases due to expensive raw materials and difficult orientation processes
Solution Approach 1:
The invention extracts and eliminates the need for expensive particle dispersion materials and complex orientation processes. Instead, it uses layered optical structures with inherent anisotropic properties that achieve the same light control function through geometric design rather than material complexity, thereby improving productivity
Solution Approach 2:
The invention replaces expensive specialized anisotropic materials with more cost-effective conventional optical materials arranged in specific layered configurations. This substitution with cheaper, easier-to-manufacture materials maintains optical performance while dramatically reducing production costs and improving manufacturing efficiency
3Illumination intensity
If a prism sheet is used separately for light condensing, then light control is achieved, but device complexity and thickness increase
Solution Approach 1:
The invention merges the diffusion function and light condensing function into a single integrated optical sheet structure. The combination of the isotropic diffusion layer and prism layer performs both functions simultaneously, eliminating the need for separate prism sheets and reducing overall device complexity and thickness
Solution Approach 2:
The integrated optical sheet achieves multi-functionality by combining diffusion and light condensing capabilities in one component. This universal design allows the single sheet to replace multiple separate optical elements, simplifying the backlight unit structure and reducing device thickness
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 anisotropic diffusion sheet achieves improved light efficiency with higher horizontal luminance and lower vertical luminance, simplifies the back light unit construction, and reduces production costs by eliminating the need for a prism sheet, resulting in a slimmer and more productive manufacturing process.
Implementation Method 1
an isotropic diffusion layer for isotropically diffusing the light incident from the light source portion by internal light scattering
Implementation Method 2
a plurality of reflectors which has an interface interfacing with the upper surface of the isotropic diffusion layer and at least one pair of the inclined surfaces disposed inclined on the upper surface of the isotropic diffusion layer, is formed to protrude from the upper surface of the isotropic diffusion layer, and is disposed at an interval on the upper surface of the isotropic diffusion layer, so as to reflect the light isotropically diffused by the isotropic diffusion layer to the display panel
Data Source
AI summary
The present invention provides an anistropic diffusion sheet, which comprises an isotropic diffusion layer for isotropically diffusing the light incident from the light source portion by internal light scattering; and a plurality of reflectors which is disposed at an interval on the upper surface of the isotropic diffusion layer, so as to reflect the light isotropically diffused by the isotropic diffusion layer to the display panel, wherein the light, emitted from the light source portion and then becomes incident to the isotropic diffusion layer, is isotropically diffused through the isotropic diffusion layer, the light isotropically illuminated by the isoptropic diffusion layer is the reflected by the plurality of reflector to be anisotropically diffuse, and this anisotropically diffused light becomes incident to the liquid crystal display panel.