Backlight Module Light Guide Plate Microstructures for Mura Reduction
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Solution Overview
Problem
Side type backlight modules using LEDs as light sources suffer from uneven light distribution, leading to mura phenomena due to non-uniform light intensities, which affect the quality of the planar light source in display devices.
Innovation Solution
The design incorporates a light guide plate with symmetric concave and convex microstructures along the light incident surface, optimized with specific curvature and distribution patterns to enhance light diffusibility and uniformity, combined with an optical film structure such as an inverse prism sheet to improve light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LEDs are arranged beside the light incident surface in intervals to serve as light sources, then the backlight module can be manufactured with current technology, but the light intensities are not evenly distributed forming bright zones and dark zones causing mura phenomenon
Solution Approach 1:
The light guide plate incorporates microstructures at specific locations (under the non-visual area) to locally enhance light diffusion. This targeted approach addresses the uneven light distribution caused by LED arrangement while maintaining manufacturing feasibility. The microstructures create localized light scattering zones that compensate for the point-source LED emission pattern.
Solution Approach 2:
The microstructures act as intermediary elements between the LED light sources and the visual area. These microstructures (protrusions or recesses) serve as light-modifying mediators that transform the non-uniform LED emission into more uniform light distribution across the visual area, eliminating bright and dark zones.
2Loss of energy
If microstructures are configured on the bottom surface to spoil total reflection and enhance light usage rate, then light diffusibility improves, but the complexity of the light guide plate increases
Solution Approach 1:
The light guide plate is segmented into functional zones: a non-visual area containing microstructures for light diffusion, and a visual area for uniform light emission. This segmentation allows the microstructures to be confined to specific regions rather than the entire surface, reducing overall complexity while maintaining effective light usage.
Solution Approach 2:
Instead of adding complex microstructures across the entire light guide plate surface, the invention inverts the approach by placing microstructures only in the non-visual area where they are most effective for light diffusion. The visual area maintains a smooth surface for uniform light emission, achieving light usage improvement without maximum complexity.
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
This configuration effectively mitigates the mura phenomenon and achieves better light uniformity across the display, enhancing the optical performance of the backlight module.
Implementation Method 1
Based on a total reflection principle, a light beam emitted by the light source is guided to the whole light guide plate after entering the light guide plate through the light incident surface
Implementation Method 2
a plurality of microstructures are configured on a bottom surface of the light guide plate to spoil the total reflection of the light beam, such that the light beam emits out from the light emitting surface of the light guide plate
Implementation Method 3
The light beam emitted from the light emitting surface further passes through the optical film disposed on the light guide plate to form the planar light source required by the display panel
Data Source
AI summary
A backlight module including an LGP, an optical film, a first light source is provided. The LGP has a bottom surface, a light emitting surface, a first light incident surface, and microstructures. Each microstructure is recessed into or protrudes out of the bottom surface and includes at least two structural units. A section line of each structural unit on a first reference plane is a curve, and the curve has a peak point. A distance between two peak points of two adjacent structural units along a first direction is greater than 0 and smaller than a half of a total width of the two structural units along the first direction. Each microstructure has a symmetric plane perpendicular to the light emitting surface and the first light incident surface. The optical film is located on the light emitting surface. The first light source is located beside the first light incident surface.