Mini LED Backlight Layout for HDR Displays With Fewer Hotspots
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Solution Overview
Problem
Existing liquid crystal displays face challenges in achieving high contrast and high dynamic range (HDR) due to the limitations of traditional backlight sources, which are not adequately matched with the grayscale presentation of the display panel.
Innovation Solution
The use of mini LEDs as a backlight source, arranged in a specific configuration on a light-emission board with a maximum size not exceeding 3 mm, and a light diffusion structure to control light emission angles and distances, ensuring minimal hotspot formation while maintaining a small thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional backlight sources are used in liquid crystal displays, then the display can be manufactured with conventional structures, but the contrast ratio and dynamic range cannot achieve high levels comparable to OLED displays
Solution Approach 1:
The backlight source is segmented into multiple independent mini LED units with maximum size not greater than 3mm, arranged in arrays on the light-emission board. This segmentation enables localized brightness control for different grayscale levels, achieving high contrast ratios comparable to OLED displays while maintaining liquid crystal display manufacturing advantages
Solution Approach 2:
The mini LED backlight units are configured to be controllable in brightness dynamically, allowing each unit or group of units to adjust its luminance according to the grayscale requirements of different display regions. This dynamic control capability enables high dynamic range (HDR) performance by matching backlight brightness with panel grayscale presentation
2Illumination intensity
If mini LED units with maximum size not greater than 3mm are used, then high dynamic range and contrast can be achieved, but the light emission may create hotspot phenomena
Solution Approach 1:
A light diffusion structure is introduced as an intermediary component between the mini LED light-emission board and the display panel. This diffusion structure scatters the light from the mini LED units, effectively reducing hotspot phenomena while preserving the high dynamic range and contrast benefits of the segmented backlight approach
Solution Approach 2:
The patent specifies precise geometric relationships between mini LED units, including the quadrangle configuration and distance constraints (minimum distance not less than D1×tanθ/2), to optimize local light distribution. These local quality controls ensure uniform light emission across the display surface, minimizing hotspots while maintaining HDR performance
3Object-affected harmful factors
If the minimum distance between display panel and light-emission board is increased to D1×tanθ/2, then hotspot phenomena are minimized, but the overall display device thickness increases
Solution Approach 1:
The light diffusion structure is implemented as a thin film or sheet with controlled thickness, allowing it to provide sufficient light scattering functionality while minimizing the increase in overall device thickness. This thin film approach enables hotspot reduction without significantly impacting the sleek profile of the display device
Solution Approach 2:
The patent optimizes the geometric parameters of the mini LED arrangement (D1 distance, θ angle) and the light diffusion structure thickness to achieve the minimum required separation distance of D1×tanθ/2. By carefully controlling these parameters, the design minimizes the thickness increase while ensuring effective hotspot reduction through proper light diffusion
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 a high dynamic range effect with reduced thickness and minimizes hotspot phenomena, enhancing the display's performance and competitiveness with organic light-emission diode displays.
Implementation Method 1
a light diffusion structure to control light emission angles and distances
Data Source
AI summary
A display device includes a display panel and a light-emission board including a base substrate and light-emission units, and a maximum size of the light-emission unit in a direction parallel to the base substrate is not greater than 3 mm; connecting lines of centers of four immediately adjacent light-emission units define a quadrangle; a connecting line of centers of two light-emission units that define the quadrangle and have a largest distance therebetween passes through two first points in edges, close to each other, of the two light-emission units; a distance between the two first points is a first distance D1; an included angle between an outermost light ray of light rays emitted by the light-emission unit and a plane parallel to the base substrate is θ; and a minimum distance between surfaces, close to each other, of the display panel and the base substrate is not less than D1*tanθ/2.