Light Guide Plate Reflective Pattern for Backlight Hot Spot Reduction
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Solution Overview
Problem
Edge-lit backlight systems in display devices face challenges in achieving adequate light diffusion rates, leading to noticeable hot spots and reduced optical efficiency, especially when minimizing the number of diffusion sheets to achieve thinner, more cost-effective designs.
Innovation Solution
A light guide plate with a reflective surface featuring a quadrilateral-shaped reflective pattern, including a concave portion with inclined surfaces and an embossed portion, is used to increase light scattering and diffusion rates, thereby improving optical efficiency and reducing hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the number of diffusion sheets is minimized to achieve thinner and more cost-effective designs, then product thickness and cost are improved, but light diffusion rate deteriorates causing noticeable hot spots
Solution Approach 1:
The reflective surface of the light guide plate is divided into multiple regions with different reflective patterns (first, second, third reflective patterns with varying densities and geometries). This local differentiation optimizes light diffusion in specific areas to eliminate hot spots while maintaining thin profile without requiring additional diffusion sheets
Solution Approach 2:
The invention transitions from using multiple planar diffusion sheets to creating three-dimensional reflective patterns (protrusions and recesses) on the reflective surface. This dimensional change enables enhanced light diffusion functionality within the same thickness constraint, resolving the contradiction between thinness and diffusion performance
2Length of stationary object
If the number of diffusion sheets is minimized to achieve thinner and more cost-effective designs, then product thickness and cost are improved, but optical efficiency deteriorates
Solution Approach 1:
Different reflective patterns are strategically placed in different regions of the light guide plate based on local optical requirements. This optimized local configuration maximizes light utilization efficiency within the thin structure, preventing energy loss that would otherwise require additional diffusion sheets
3Illumination intensity
If reflective patterns with higher density are used to improve light diffusion, then light diffusion rate is improved, but manufacturing complexity increases
Solution Approach 1:
The reflective patterns are designed with specific geometric parameters (protrusion heights, recess depths, pattern densities) that can be adjusted to achieve desired diffusion effects. These parameter variations allow optimization of light diffusion while maintaining compatibility with standard manufacturing processes like injection molding or embossing
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 scattering and diffusion capabilities of the light guide plate improve image uniformity, luminance, and optical efficiency, while minimizing hot spots and maintaining a slim, cost-effective design.
Implementation Method 1
a scattering rate or diffusion rate of light outputted from a light guide plate can be increased by scattering light by a concave portion and an embossed portion
Implementation Method 2
a reflective surface positioned at the opposite side of the light output surface
Data Source
AI summary
The present invention relates to a light guide plate, and a backlight unit and display device including the same. According to an aspect of the present invention, there is provided a light guide plate, including: a light output surface configured to output light toward the outside; a reflective surface positioned at the opposite side of the light output surface; a light incident surface provided on at least one side surface among the side surfaces connecting the light output surface to the reflective surface to receive light irradiated from a light source; and a reflective pattern having a quadrilateral shape when viewed in a direction perpendicular to the reflective surface, and having a concave portion recessed toward an inner portion of the reflective surface and an embossed portion protruding from an edge of the concave portion toward an outer portion of the reflective surface.