Concavo-Convex Light Conversion Layer for Backlight Brightness
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Solution Overview
Problem
Conventional backlight units for LCDs face challenges in achieving high brightness uniformity and color reproduction, particularly in larger displays, where direct-illumination type backlight units require increased thickness to maintain brightness while edge-illumination types struggle with limited light sources.
Innovation Solution
A light conversion layer with a concavo-convex pattern is integrated into the optical member, which includes a substrate with embossed convex parts and corresponding concave surfaces, allowing for efficient wavelength conversion and improved light path length, enhancing brightness and color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If direct-illumination type backlight unit is used to achieve high brightness, then brightness is improved, but thickness increases
Solution Approach 1:
The patent applies parameter changes by modifying the refractive index parameters of the light conversion layer and surrounding optical elements. By optimizing the refractive index difference between the light conversion layer and adjacent layers, the patent enhances light extraction efficiency and brightness without requiring increased thickness, thus resolving the contradiction between brightness and thickness.
Solution Approach 2:
The patent implements local quality by creating a light conversion layer with spatially varying properties - specifically, a concavo-convex pattern that introduces local variations in refractive index and light path. This localized structural modification improves light extraction at critical interfaces without requiring the entire backlight unit to be thicker, thereby achieving high brightness while maintaining compact thickness.
2Manufacturing precision
If quantum dot bar is used to convert blue light to white light, then color reproduction is improved, but device complexity increases
Solution Approach 1:
The patent merges the light conversion function directly into the light guide plate structure by integrating the light conversion layer as an embedded component. This consolidation eliminates the need for separate quantum dot bar assemblies and their associated mounting structures, thereby maintaining superior color reproduction while reducing overall device complexity and assembly steps.
Solution Approach 2:
The light guide plate is designed to serve multiple functions simultaneously: it acts as both the light guiding structure and the light conversion medium through the integrated light conversion layer. This multi-functionality eliminates the need for separate dedicated light conversion components, reducing device complexity while preserving the color reproduction benefits of quantum dot conversion.
3Length of stationary object
If light conversion layer with concavo-convex pattern is used, then light path length is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs curvature by introducing a concavo-convex pattern with rounded features into the light conversion layer. This curved geometric structure effectively increases the light path length through multiple internal reflections and refractions, while the smooth rounded contours are more amenable to standard manufacturing processes compared to sharp angular features, thereby balancing enhanced light path length with reasonable manufacturing precision requirements.
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 superior color reproduction and brightness by effectively converting light wavelengths and improving light linearity and dispersibility, addressing the thickness and brightness uniformity issues in conventional backlight units.
Implementation Method 1
a quantum dot bar having a plurality of quantum dots, which can convert blue light into red light or green light, is positioned in front of a blue LED that emits the blue light. Thus, as the blue light is irradiated onto the quantum dot bar, the blue light, the red light and the green light are mixed and the mixed light is incident into the light guide plate, thereby generating white light.
Data Source
AI summary
Disclosed are an optical member and a display device. The display device includes a light source; a light conversion layer to convert a wavelength of light emitted from the light source; and a display panel into which the light is incident from the light conversion layer. Further, the light conversion layer includes a plurality of concave surfaces.