Light Guide Plate Stripe Microstructures for Backlight 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 sources, leading to poor appearance brightness uniformity and hot spots on the light incidence side.
Innovation Solution
A light guide plate with microstructure regions on its light-emitting surface, featuring stripe or dot microstructures parallel or perpendicular to the light incidence surface, which scatter incident light to blur leakage and improve brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If point light sources (LEDs) are used in backlight modules, then energy efficiency and lifespan are improved, but light leakage and uneven brightness occur due to the directional nature of the light sources
Solution Approach 1:
The patent applies local quality by creating a microstructure region with different optical properties than the rest of the light guide plate. This microstructure region, located near the light incidence surface, contains scattered light paths that specifically address the directional light leakage problem in that localized area without affecting the overall light guide function
Solution Approach 2:
The patent introduces a new dimension by adding microstructures (prisms, gratings, or rough surfaces) to the light guide plate's internal surface. These microstructures create additional light scattering paths in multiple dimensions, converting the highly directional point source light into a more uniform distributed light source
2Illumination intensity
If the cover's covering range is extended to prevent light leakage, then appearance brightness uniformity is improved, but the non-visible region increases and hot spots remain
Solution Approach 1:
The patent applies preliminary action by pre-scattering the light from point sources before it reaches the cover's visible region. The microstructure region is positioned to intercept and scatter light early in its path, preventing the formation of hot spots and light leakage before they become visible, thus reducing the need for an extended cover
3Illumination intensity
If microstructure regions with scattered light paths are added to the light guide plate, then light leakage is reduced and brightness uniformity is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the optical parameters of the light guide plate through the addition of microstructures. Rather than changing the fundamental structure or material composition significantly, it alters the surface morphology and light path parameters locally, achieving improved uniformity with minimal complexity increase
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 microstructures effectively scatter light, reducing light leakage and enhancing brightness uniformity across the backlight module, resulting in a more uniform and improved appearance brightness distribution.
Implementation Method 1
The 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
The dot microstructures can blur light reflected back to a light-emitting surface of the light guide plate
Data Source
AI summary
A light guide plate and a backlight module are described. The light guide plate includes a main body and a plurality of stripe microstructures. The main body includes a light incidence surface, a light-emitting surface and a light reflective surface. The light-emitting surface is opposite to the light reflective surface, and the light incidence surface is connected between the light-emitting surface and the light reflective surface. The light-emitting surface includes a microstructure region adjacent to the light incidence surface. The stripe microstructures are arranged in the microstructure region, and parallel to a normal line of the light incidence surface.