Diffuser Board Micro-Lens Design for LED Backlight Mura Elimination
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Solution Overview
Problem
Liquid-crystal display devices using point light sources, such as LEDs, suffer from striped mura due to inadequate light diffusion, leading to uneven illumination on the panel surface.
Innovation Solution
A diffuser board with specifically designed diffusion patterns is placed between the point light sources and the liquid crystal panel, diffusing light uniformly to prevent mura by arranging prism patterns or micro lenses according to the positions and number of point light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a point light source (LED) is used as backlight, then the device can be made thinner and energy consumption is reduced, but striped mura appears on the liquid crystal panel due to inadequate light diffusion
Solution Approach 1:
A diffuser board is introduced as an intermediary component between the LED point light source and the liquid crystal panel. This diffuser board includes diffusion portions with micro-lenses that mediate the light transmission, transforming the point source light into uniformly diffused light and eliminating striped mura while maintaining the thin profile enabled by LED backlighting
2Object-affected harmful factors
If a linear light source (fluorescent lamp) is used, then light diffusion is effective and uniform illumination is achieved, but the device thickness increases
Solution Approach 1:
The invention changes the light source parameter from linear (fluorescent lamp) to point source (LED), and compensates for the resulting diffusion deficiency by introducing a diffuser board with micro-lenses. This parameter change enables thinner device thickness while maintaining uniform illumination through optical engineering rather than relying on linear light source geometry
3Length of moving object
If the distance between light source and liquid crystal panel is reduced to make the backlight thinner, then device thickness is reduced, but striped mura becomes more pronounced
Solution Approach 1:
The diffuser board serves as a necessary intermediary that enables the light source to be positioned close to the panel while preventing striped mura. The micro-lenses on the diffuser board actively diffuse the light even at short distances, allowing the system to achieve thin backlight profile without sacrificing illumination uniformity
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 effectively diffuses light emitted by LED modules, ensuring uniform illumination across the liquid crystal panel and preventing the occurrence of mura, even when using point light sources as backlighting.
Implementation Method 1
a diffuser board with specifically designed diffusion patterns is placed between the point light sources and the liquid crystal panel, diffusing light uniformly
Implementation Method 2
forms diffusion patterns on the diffuser board according to the positions and number of point light sources
Data Source
AI summary
An object of the present invention is to provide a liquid-crystal display device which includes a diffuser board that does not produce striped mura on the surface of a liquid crystal panel even if point light sources are used as light sources of a backlight.A backlight apparatus 103 is provided with a diffuser board 103b having diffusion portions 103b1. At each of the diffusion portions 103b1, the light L emitted by a LED module 104 included in a light source unit 103a is reflected by prism patterns P and diffused around the LED module 104. Then, the diffused light is reflected again by a reflecting surface formed on the inner surface of a housing 103c and emitted from the backlight apparatus 103, thereby achieving illuminating light without mura.