Light Guide Plate Stripe Microstructures for Brightness Uniformity
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Solution Overview
Problem
Conventional backlight modules with point light sources, such as LEDs, suffer from light leakage and uneven brightness due to the directional nature of the light emission, leading to poor appearance brightness uniformity and hot spots on the light incidence side.
Innovation Solution
A light guide plate with first and second stripe microstructures on its light-emitting surface, where the first microstructures scatter incident light in the non-visible region and the second microstructures vary in shape, angle, height, or arrangement to enhance luminance and uniformity, effectively blurring leakage light and improving brightness distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If point light sources (LEDs) are used to replace linear light sources, then energy efficiency and lifespan are improved, but light leakage and uneven brightness occur due to the directional nature of light emission
Solution Approach 1:
The patent applies local quality by introducing different microstructure types at different locations on the light guide plate. First microstructures (e.g., protrusions) are placed in regions requiring light scattering to address leakage, while second microstructures (e.g., holes) are placed in regions requiring light extraction to address uneven brightness. This spatial differentiation of microstructure functions resolves the contradiction between energy efficiency and brightness uniformity.
Solution Approach 2:
The patent segments the light guide plate surface into multiple regions with different microstructure configurations. The light guide plate is divided into a first region with first microstructures and a second region with second microstructures, allowing each segment to address specific local optical issues. This segmentation enables the system to maintain high energy efficiency while achieving overall brightness uniformity through localized optical control.
2Device complexity
If the cover length is reduced, then device compactness is improved, but light leakage in the non-visible region increases significantly
Solution Approach 1:
The patent converts the harmful light leakage phenomenon into a beneficial effect by strategically placing first microstructures in the non-visible region. These microstructures scatter the leakage light that would otherwise be harmful, transforming it into uniformly distributed ambient light. This allows the cover to be shortened while maintaining optical performance, as the scattered light from the first microstructures compensates for the reduced cover length.
Solution Approach 2:
The first microstructures act as an intermediary element between the light guide plate and the cover. They mediate the interaction by scattering light in the non-visible region, preventing direct light leakage while allowing indirect light diffusion. This intermediary mechanism enables compact device design without sacrificing optical control.
3Illumination intensity
If microstructures are added to scatter light and improve uniformity, then brightness uniformity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs parameter changes by varying the geometric characteristics of microstructures (size, shape, depth, spacing) across different regions of the light guide plate. First microstructures have different parameters than second microstructures, allowing optimization of light scattering and extraction independently. This parameter differentiation achieves brightness uniformity while maintaining manufacturability through systematic variation rather than complex multi-component designs.
Solution Approach 2:
The patent creates a composite microstructure system combining two distinct types of microstructures (protrusions and holes) with different optical functions. This composite approach allows the light guide plate to simultaneously perform light scattering and light extraction functions, achieving brightness uniformity through the synergistic effect of combined microstructure types rather than a single complex microstructure design.
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 significantly reduces light leakage and enhances brightness uniformity across the light-emitting surface, eliminating hot spots and improving the overall visual effect of the backlight module.
Implementation Method 1
The first stripe microstructures can scatter incident light of a non-visible region, so that leakage light on the non-visible region can be effectively blurred
Implementation Method 2
Light 110 emitted by the light-emitting diodes 108 enters the light guide plate 102 through the light incidence surface 106, and is emitted out of the light guide plate 102 through the light-emitting surface 104 of the light guide plate 102 after being guided by the light guide plate 102
Data Source
AI summary
A light guide plate and a light source module are described. The light guide plate includes a main body, first stripe microstructures and second stripe microstructures. The main body includes a light incidence surface and an optic surface. The light incidence surface is connected to the optic surface. The optic surface includes a first microstructure region and a second microstructure region arranged sequentially, and the first microstructure region is near the light incidence surface. The first stripe microstructures are disposed in the first microstructure region and extending along a direction from one side near the light-incident surface to the other side away from the light-incident surface. The second stripe microstructures are disposed in the second microstructure region along the direction. A gradient of each second stripe microstructure is gradually varied along the direction.