Light Guide Plate With Layered Scattering Concentration
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Solution Overview
Problem
Existing backlight units for large-sized liquid crystal televisions face challenges in reducing thickness while maintaining high light use efficiency and uniform luminance, often resulting in increased costs and complexity due to complex shapes and materials, and are prone to unevenness and warping issues.
Innovation Solution
A light guide plate with a two-layer structure, where the first layer is closer to the light exit surface and the second layer is closer to the rear surface, with scattering particles at different concentrations, allowing for a thin design with a convex or bell-shaped brightness distribution, reduced return light, and improved diffusion of incident light to prevent bright lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a light guide plate with scattering particles is used to reduce thickness, then the thickness is reduced, but the light use efficiency decreases and luminance unevenness occurs
Solution Approach 1:
The light guide plate employs different scattering particle concentrations in different regions: higher concentration near the light incidence surface to enhance light diffusion and reduce return light, and lower concentration near the light exit surface to maintain light transmission efficiency. This local differentiation resolves the contradiction by optimizing light management at each zone rather than using uniform concentration throughout.
Solution Approach 2:
The invention transitions from a single-layer uniform structure to a multi-layer non-uniform structure, adding the dimension of vertical stratification. By dividing the light guide plate into multiple layers with different scattering particle concentrations, the system achieves both thinness and high light use efficiency through optimized light path management in each layer.
2Illumination intensity
If a light guide plate with non-uniform thickness is used to improve light distribution, then luminance unevenness is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
Instead of changing the geometric shape or thickness of the light guide plate to achieve uniform luminance, the invention changes the optical parameter of scattering particle concentration. By varying the concentration of scattering particles within a uniform plate structure, the system achieves improved light distribution without increasing structural complexity or manufacturing difficulty.
3Ease of manufacture
If scattering particles are uniformly distributed in the light guide plate, then manufacturing is simple, but return light and bright lines appear causing unevenness
Solution Approach 1:
The invention applies local quality by concentrating scattering particles in specific regions (higher concentration near light incidence, lower concentration near light exit). This non-uniform distribution reduces return light and eliminates bright lines while maintaining manufacturability through standard injection molding processes capable of producing gradient particle concentrations.
4Length of stationary object
If the light guide plate is made thinner to reduce overall size, then the device becomes more compact, but light diffusion is insufficient causing bright lines
Solution Approach 1:
The invention compensates for reduced thickness by changing the optical parameter of scattering particle concentration. Higher concentration of scattering particles in the region near the light incidence surface enhances light diffusion within the thinner plate, preventing bright lines while maintaining compact dimensions.
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 achieves a high light use efficiency with reduced unevenness in luminance, enabling a thinner and more cost-effective backlight unit with improved light distribution and reduced manufacturing complexity.
Implementation Method 1
a light guide plate which receives light emitted from an illumination light source, guides the received light in predetermined directions and emits the guided light through a light exit surface
Implementation Method 2
improved diffusion of incident light to prevent bright lines
Data Source
AI summary
The light guide plate includes two or more layers superposed on each other in a direction substantially perpendicular to a light exit surface and containing scattering particles at different particle concentrations. The thicknesses of the two or more layers in the direction substantially perpendicular to the light exit surface are changed so that the combined particle concentration of the light guide plate has, in a direction perpendicular to at least one light incidence surface, a first local maximum value on at least one side closer to the at least one light incidence surface and a second local maximum value located at a position farther from the at least one light incidence surface than at least one position of the first local maximum value and being larger than the first local maximum value.