Light Guide Plate Reflection Pattern for Uniform Illumination
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Solution Overview
Problem
Edge-lit type backlights face challenges in securing adequate light diffusion and often result in hot spots due to limited light diffusion capabilities, which affects the image quality and overall performance of ultra-thin display products.
Innovation Solution
A light guide plate with a reflection pattern featuring an embossed circular portion and a surrounding ring-shaped concave portion, where the centers of these features are offset, is used to enhance light scattering and diffusion, thereby improving the light distribution and reducing hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If an edge-lit type backlight is used to reduce product thickness, then the product thickness is reduced, but the light diffusion degree is insufficient and hot spots occur
Solution Approach 1:
The reflective surface is divided into multiple regions with different reflection characteristics. The first reflection region has a first reflection ratio while the second reflection region has a second reflection ratio different from the first. This local variation in reflection properties enables different areas to contribute differently to light diffusion, improving overall light distribution uniformity while maintaining the edge-lit thin structure.
Solution Approach 2:
The patent changes the reflection ratio parameter across different regions of the reflective surface. By adjusting the reflection ratio from one region to another, the light path and distribution are optimized to enhance diffusion without requiring additional diffusion sheets, thus maintaining thin profile while improving illumination uniformity.
2Length of stationary object
If conventional diffusion sheets are reduced to achieve ultra-thin design, then product thickness is reduced, but luminance uniformity deteriorates due to insufficient light diffusion
Solution Approach 1:
Different regions of the reflective surface are assigned different reflection ratios to create localized light control. The first reflection region and second reflection region have deliberately different optical properties, allowing precise control over light distribution patterns to maintain luminance uniformity without conventional diffusion sheets.
Solution Approach 2:
The patent replaces the mechanical diffusion system (conventional diffusion sheets) with an optical control system based on spatially varying reflection ratios. This substitution achieves light diffusion functionality through optical design rather than physical diffusion media, enabling ultra-thin design while maintaining luminance uniformity.
3Ease of manufacture
If a simple reflective surface is used in edge-lit backlight, then manufacturing complexity is reduced, but hot spots are generated due to poor light distribution
Solution Approach 1:
The reflective surface incorporates regions with different reflection ratios to create controlled light scattering patterns. This local differentiation in optical properties eliminates hot spots by ensuring uniform light distribution across the display area, while the overall structure remains compatible with standard manufacturing processes.
Solution Approach 2:
The reflective surface design introduces asymmetry in reflection ratios between different regions. This asymmetric optical design breaks the symmetry of light reflection paths, preventing concentrated light spots and achieving uniform illumination without requiring complex manufacturing techniques.
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 enhanced light diffusion and scattering capabilities of the light guide plate lead to improved luminance uniformity and reduced hot spots, resulting in better image quality and display performance.
Implementation Method 1
light is scattered by the embossed portion and the concave portion in the light guide plate, and thus a degree of scattering or diffusion of the light output from the light guide plate can be improved
Data Source
AI summary
Provided are a light guide plate, and a backlight unit and a display device including the same. A light guide plate includes a light output surface configured to output light to the outside; a reflective surface positioned opposite the light output surface; a light incident surface provided on at least one side surface of side surfaces which connect the light output surface and the reflective surface, and configured to receive light projected from a light source; and a reflection pattern including an embossed portion having a circular shape and configured to protrude to the outside of the reflective surface when viewed in a direction perpendicular to the reflective surface, and a concave portion having a ring shape which surrounds the embossed portion and recessed in the reflective surface when viewed in a direction perpendicular to the reflective surface. Here, the center of the embossed portion is provided to be different from the center of the concave portion.