RGB LED Backlight DBR Structure for Thin Display Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display apparatuses are becoming thinner, necessitating reduced optical distances while maintaining brightness and uniformity, which existing technologies struggle to achieve with conventional backlight units.
Innovation Solution
A backlight unit configuration using red, green, and blue light emitting diodes with distributed Bragg reflectors (DBRs) that maintain similar reflectivities across varying incident angles, employing titanium dioxide and silicon dioxide layers with varying thicknesses to optimize light diffusion and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the optical distance is reduced to make the display apparatus thinner, then the thickness is reduced, but the brightness and uniformity of brightness deteriorate
Solution Approach 1:
The patent applies local quality by configuring different DBR structures for different color LEDs (red, green, blue) with specific reflectivity characteristics. Each color LED has a DBR designed to reflect its specific wavelength range, creating localized optical optimization that ensures uniform brightness across the display even with reduced optical distance.
Solution Approach 2:
The patent changes optical parameters by designing DBRs with specific reflectivity ranges (90-95% for red, 85-90% for green, 80-85% for blue) and controlling the incident angle ranges for each color. This parameter optimization allows the system to maintain brightness uniformity while reducing the optical distance to achieve thinner display apparatus.
2Length of stationary object
If the optical distance is reduced to make the display apparatus thinner, then the thickness is reduced, but the uniformity of brightness deteriorates
Solution Approach 1:
The patent implements local quality by assigning specific DBR configurations to different spatial locations and color channels. Each DBR is optimized for its specific position and wavelength, ensuring that light reflection characteristics are uniformly controlled across the entire display area despite the reduced optical distance.
Solution Approach 2:
The patent achieves equipotentiality by balancing the reflectivity characteristics of DBRs across all color LEDs (red, green, blue) so that they all contribute equally to the overall brightness uniformity. The incident angle ranges and reflectivity values are carefully matched to ensure uniform optical performance across the display surface.
3Ease of manufacture
If distributed Bragg reflectors with different reflectivities are used for different color LEDs, then color reproduction may be improved, but light diffusion uniformity deteriorates
Solution Approach 1:
The patent optimizes parameters by setting specific reflectivity ranges for each color DBR (red: 90-95%, green: 85-90%, blue: 80-85%) and matching their incident angle ranges. This parameter coordination ensures that while each color has optimized reflectivity for good color reproduction, the overall light diffusion remains uniform across all colors.
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
Enhances light diffusing function, increases contrast ratio, and improves color reproduction in thinner display apparatuses by ensuring consistent reflectivity across different angles.
Implementation Method 1
a distributed Bragg reflector (DBR) provided on the light emitting layer, and wherein reflectivities of the distributed Bragg reflectors of the red light emitting diode, the green light emitting diode, and the blue light emitting diode are within a same range of reflectivity according to an incident angle of light incident on the distributed Bragg reflectors
Data Source
AI summary
A display apparatus includes a liquid crystal panel; and a backlight unit configured to provide light to the liquid crystal panel, wherein the backlight unit includes: a substrate; and a plurality of light emitting diode groups provided on an upper surface of the substrate, wherein each of the plurality of light emitting diode groups includes a red light emitting diode, a green light emitting diode, and a blue light emitting diode, wherein each of the red light emitting diode, the green light emitting diode, and the blue light emitting diode includes: a light emitting layer; and a distributed Bragg reflector (DBR) provided on the light emitting layer, and wherein reflectivities of the distributed Bragg reflectors of the red light emitting diode, the green light emitting diode, and the blue light emitting diode are within a same range of reflectivity according to an incident angle of light incident on the DBRs.