Optical Member Refractive Index Gradient for Display Brightness
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Solution Overview
Problem
Conventional backlight units in LCDs face challenges in achieving brightness uniformity and high color reproduction, particularly with the direct-illumination type backlight units requiring increased thickness to ensure brightness uniformity and the need for improved optical characteristics.
Innovation Solution
An optical member with a receiving member having a light incident part and a light exit part of different refractive indices, along with wavelength conversion particles, is integrated between the light source and the light guide plate to enhance light efficiency and reduce reflection losses, thereby improving the optical characteristics and brightness of the display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a direct-illumination type backlight unit is used to supply light over the whole area of the liquid crystal display panel, then high brightness can be achieved, but the thickness must be larger to ensure brightness uniformity
Solution Approach 1:
The backlight unit is divided into multiple light sources arranged in an array pattern, with each light source independently controllable. This segmentation allows localized brightness adjustment to achieve uniform overall illumination without increasing total thickness
Solution Approach 2:
The backlight unit employs dynamically controllable light sources where individual LEDs can be adjusted in intensity. This dynamic control enables compensation for thickness variations and achieves brightness uniformity across the display panel
2Illumination intensity
If quantum dot bars are positioned in front of blue LED to convert blue light into red and green light, then high color reproduction may be realized, but the device complexity increases
Solution Approach 1:
Quantum dot layers are applied locally at specific positions between light sources and the liquid crystal panel, rather than uniformly throughout the entire backlight structure. This localized application achieves color conversion while minimizing added complexity
Solution Approach 2:
The patent uses quantum dot materials with specific size ranges (2-10 nm) to achieve wavelength conversion. These composite material structures enable high color reproduction by converting blue LED light into precise red and green wavelengths
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 improved light incident and exit efficiencies, reducing reflection losses and enhancing the optical characteristics and brightness of the display device, allowing for better color reproduction and uniformity.
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
Implementation Method 2
According to the edge-illumination type backlight unit, the light source is located at a lateral side of a light guide plate
Data Source
AI summary
Disclosed are an optical member and a display device including the same. The optical member includes a receiving member; a host in the receiving member; and a plurality of wavelength conversion particles distributed in the host. The receiving member includes a light incident part having a first refractive index; and a light exit part having a second refractive index different from the first refractive index. The optical member improves the optical characteristics by adjusting the refractive indexes of the light incident part and the light exit part.