Backlight Module Wedge Light Guide and Concave Reflector
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Solution Overview
Problem
Conventional side-type backlight modules using light emitting diodes often suffer from the 'hot spot' phenomenon due to insufficient light mixing, leading to non-uniformity in the planar light source, which affects the optical quality of liquid crystal display panels.
Innovation Solution
A backlight module design featuring a light guiding plate with a progressively decreasing thickness from the side surface towards the light incident surface, combined with a block having a concave reflecting surface that reflects light back into the plate, increasing the light mixing distance and reducing hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional side-type backlight module uses light emitting diodes beside the light guiding plate, then the light source structure is simple, but the hot spot phenomenon occurs due to insufficient light mixing distance
Solution Approach 1:
The patent introduces a wedge-shaped light guiding plate with varying thickness, transforming the uniform thickness structure into a gradient thickness structure. This dimensional change increases the light mixing path length without adding complex components, effectively reducing hot spots while maintaining structural simplicity
Solution Approach 2:
The light guiding plate is designed with different thicknesses at different locations - thinner at the light incident surface and thicker at the opposite surface. This local variation in quality (thickness) optimizes light mixing in different regions, preventing hot spots near the light source while ensuring uniform light output
2Ease of manufacture
If the light guiding plate has uniform thickness, then the manufacturing process is simple, but the light mixing distance is insufficient causing non-uniform light distribution
Solution Approach 1:
The patent changes the thickness parameter of the light guiding plate from a constant value to a gradient value that varies continuously from the light incident surface to the opposite surface. This parameter change increases the light mixing distance and improves light distribution uniformity while remaining manufacturable through standard molding processes
3Illumination intensity
If the light guiding plate thickness decreases from side surface towards light incident surface, then the light mixing distance is increased, but the structural complexity increases
Solution Approach 1:
The patent utilizes the thickness dimension of the light guiding plate to create the wedge shape, transforming a two-dimensional uniform plate into a three-dimensional gradient structure. This approach increases light mixing distance by utilizing the existing structural dimension rather than adding separate components
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 design enhances light uniformity and optical quality by increasing the light mixing distance, reducing the hot spot phenomenon, and improving overall light utilization, resulting in a more uniform planar light source.
Implementation Method 1
The reflecting surface is a concave surface recessed into the block. The reflecting surface is configured to reflect the light beam back to the side surface.
Implementation Method 2
the light beam from the light incident surface is totally internal reflected at the first surface or the second surface of the light guiding plate
Implementation Method 3
refracted by the first surface or the second surface to the outside of the light guiding plate
Data Source
AI summary
A backlight module including a light guiding plate, a light source and a block is provided. The light guiding plate includes a first surface, a second surface opposite to the first surface, a light incident surface connecting to the first surface and the second surface, and a side surface opposite to the light incident surface. A thickness of at least part of the light guiding plate decreases progressively from the side surface towards the light incident surface. The light source is disposed beside the light incident surface and is capable of emitting a light beam into the light guiding plate through the light incident surface. The block is disposed beside the side surface and includes a reflecting surface facing towards the side surface. The reflecting surface is a concave surface on the block, and the reflecting surface is capable of reflecting the light beam returning to the side surface.