Direct-Lit Backlight Air-Gap Layout for Mura Reduction
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Solution Overview
Problem
Direct-lit backlight modules suffer from uneven brightness (Mura) due to the lack of an air layer between the reflective member and optical film layer, necessitating additional diffusion structures that increase cost and power consumption.
Innovation Solution
A direct-lit backlight module design with a substrate, optical film layer, and reflective structures surrounding light-emitting elements, featuring a controlled air layer thickness ratio (0.4≤X≤0.6) between the reflective structures and optical film layer, which enhances light mixing and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the air layer thickness is reduced or eliminated to reduce module thickness, then the backlight module thickness is reduced, but uneven brightness (Mura) occurs in the display screen
Solution Approach 1:
The patent applies parameter changes by optimizing the air layer thickness to a specific range (0.3-1.5mm) rather than eliminating it entirely. This controlled parameter adjustment allows the system to achieve both reduced thickness and improved brightness uniformity, resolving the contradiction between compactness and optical performance.
Solution Approach 2:
The air layer acts as an intermediary between the reflective member and optical film layer, facilitating light mixing and uniformity. By introducing this intermediate medium with controlled thickness, the patent enables both thin module design and effective light distribution, eliminating the need for additional diffusion structures.
2Illumination intensity
If additional diffusion structures are added to optical film layers to fix Mura, then brightness uniformity is improved, but cost and power consumption increase
Solution Approach 1:
The patent extracts the light mixing function from the optical film layers and relocates it to the air layer between the reflective member and optical film layer. This extraction eliminates the need for complex diffusion structures within the optical film layers, simplifying the overall device while maintaining brightness uniformity.
Solution Approach 2:
The air layer serves as an intermediary that performs the light mixing function previously requiring complex optical film structures. This simple intermediary medium achieves the same brightness uniformity effect without increasing device complexity or requiring additional diffusion layers.
3Illumination intensity
If additional diffusion structures are added to fix Mura, then brightness uniformity is improved, but power consumption increases
Solution Approach 1:
The patent extracts the light mixing function from energy-intensive optical film diffusion structures and implements it through the simple air layer. This extraction eliminates the need for additional power-consuming diffusion components while maintaining brightness uniformity, directly reducing overall power consumption.
Solution Approach 2:
The patent replaces complex, energy-intensive diffusion structures with a simple air layer that requires no power consumption. This substitution uses a passive, low-cost medium to achieve the same functional effect, significantly reducing the power consumption of the backlight module.
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 design improves picture quality by reducing Mura and controlling halo, maintaining a thin module thickness while optimizing light distribution and reducing power consumption.
Implementation Method 1
there is air in the gap between the reflective structures and the optical film layer
Implementation Method 2
enhances light mixing and uniformity
Implementation Method 3
the reflector is located between the substrate and the optical film layer and includes a plurality of reflective structures surrounding the plurality of light-emitting elements
Data Source
AI summary
A direct-lit backlight module, a method of designing a backlight module and a display device are provided. The direct-light backlight module includes a substrate; an optical film layer; a reflector; and light-emitting elements. The substrate and the optical film layer are arranged oppositely; the light-emitting elements are arranged on a side of the substrate facing the optical film layer; the reflector is located between the substrate and the optical film layer and includes reflective structures surrounding the light-emitting elements; there is a gap between the reflective structures and the optical film layer, and there is air in the gap. In the thickness direction of the backlight module, a distance between one end of the reflective structure adjacent to the optical film layer and the optical film layer is OD1, and the distance between the substrate and the optical film layer is OD; andX=OD1OD;and 0.4≤X<0.6.