Anisotropic Lens Backlight for Uniform Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional display devices face challenges in achieving uniform surface light distribution and reducing the number of light sources, leading to inefficiencies in light efficiency and illumination uniformity, particularly with isotropic light distribution structures.
Innovation Solution
The display apparatus incorporates a backlight unit with a lens structure that totally reflects light emitted from light-emitting elements, using an anisotropic light distribution and a reflective layer with inclined surfaces to improve light efficiency and uniformity, reducing the thickness and weight of the unit, and eliminating the need for a separate light-guiding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If isotropic lens structure with orthogonally arranged light sources is used, then light distribution is uniform in all directions, but the pitch between light sources increases making it difficult to spread light effectively
Solution Approach 1:
The patent applies asymmetry by designing an anisotropic lens with different refractive indices in different directions (nx ≠ ny). The lens has a specific asymmetric structure where the curvature radius in the row direction (R1) differs from the curvature radius in the column direction (R2), enabling directional light control that overcomes the limitation of isotropic lenses and allows effective light spreading with fewer light sources.
Solution Approach 2:
The patent changes optical parameters by defining specific relationships between refractive indices (nx, ny, nz) and curvature radii (R1, R2) to achieve the desired light distribution. By adjusting these parameters according to the formulas provided in the patent, the lens can control light propagation angles and achieve uniform illumination with reduced light source density.
2Device complexity
If the number of light sources is reduced, then device complexity decreases, but light efficiency and illumination uniformity deteriorate
Solution Approach 1:
The patent optimizes optical parameters including refractive indices and curvature radii to maximize light extraction efficiency. The specific parameter relationships defined in the patent enable the anisotropic lens to redirect light effectively, ensuring high light efficiency even with reduced light source density.
Solution Approach 2:
The patent applies local quality by creating direction-dependent optical properties in the lens. The anisotropic structure provides different refractive behaviors in different directions, allowing optimized light control locally in specific directions to maintain overall illumination uniformity with fewer light sources.
3Illumination intensity
If conventional backlight unit structure is used, then light distribution is achieved, but thickness of the backlight unit increases
Solution Approach 1:
The patent extracts and eliminates the light-guiding layer from the conventional backlight unit structure. By using the anisotropic lens directly to control and distribute light, the patent removes the need for a separate light-guiding layer, thereby reducing the overall thickness of the backlight unit while maintaining effective light distribution.
Solution Approach 2:
The anisotropic lens performs multiple functions simultaneously: it controls light direction, achieves uniform illumination distribution, and replaces the function previously required by a separate light-guiding layer. This multi-functionality reduces the number of components and overall 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
This configuration enhances image quality by improving light efficiency and illumination uniformity, allowing for a thinner and lighter display apparatus with reduced light sources, while maintaining consistent brightness across the display panel.
Implementation Method 1
the lens section includes an entrance surface on which light from the light-emitting element is incident; an exit surface from which the light incident on the entrance surface is emitted
Implementation Method 2
a reflective layer with inclined surfaces to improve light efficiency and uniformity
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
A display apparatus according to an embodiment of the present disclosure comprises: a substrate; a light-emitting unit including a light emitting element mounted on the substrate and a lens placed above the light-emitting element; a reflective layer placed on the upper surface of the substrate; an optical sheet placed above the reflective layer and placed at a height at which the optical sheet is spaced from the light-emitting unit; and a display panel placed on the upper surface of the optical sheet, wherein the lens has a cutout portion formed therein by depressing a part of the side surface thereof toward the center thereof, thereby providing an anisotropic light distribution.