Backlight Module LED Diffusion Layer Light Shadow Elimination
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Solution Overview
Problem
In side-lit liquid crystal display devices, misalignment between LED light bars and light guide plates creates non-light source areas and light shadows due to the discrete nature of LEDs, affecting display performance, especially when the reflection sheet deforms.
Innovation Solution
A diffusion layer comprising a transparent adhesive and light diffusion particles, including organic and inorganic particles, is applied to the light emitting surface of LEDs to increase the distribution angle of light, transitioning from a point source to a line source, ensuring uniform brightness and eliminating dark areas between LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are arranged side by side as point light sources, then the backlight module can provide illumination for the liquid crystal display panel, but non-light source areas and light shadows are formed between adjacent LEDs due to misalignment with the light guide plate
Solution Approach 1:
The patent transforms the light source from point sources (0D) to line sources (1D) by wrapping LED light bars around the light guide plate. This dimensional change ensures continuous light coverage and eliminates the non-light source areas that occur with discrete point LED arrangements, solving the alignment precision problem inherently.
Solution Approach 2:
The LED light bars are pre-formed and designed to match the curvature and dimensions of the light guide plate before assembly. This preliminary preparation ensures precise alignment when the LED light bars are wrapped around the light guide plate, preventing misalignment and light shadow formation.
2Adaptability or versatility
If the reflection sheet on the side of the LEDs is deformed, then the non-light source area increases, but this causes clear LED light paths and light shadows to form on the light incident side
Solution Approach 1:
By transforming from point sources to line sources through wrapping LED light bars around the light guide plate, the system creates continuous light coverage that is inherently more tolerant to reflection sheet deformations. The continuous line source ensures that even if the reflection sheet deforms, light paths remain uniform without forming distinct light shadows.
3Device complexity
If discrete LEDs are used as point light sources, then the structure is simple, but the brightness distribution is non-uniform with dark areas between LEDs
Solution Approach 1:
The patent transitions from discrete point sources (0D) to continuous line sources (1D) by wrapping LED light bars around the light guide plate. This dimensional transformation maintains structural simplicity while achieving uniform brightness distribution, as the continuous line source eliminates dark areas between discrete LEDs.
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 enhances light uniformity and brightness, preventing misalignment issues and light shadows, thereby improving the display performance of liquid crystal display devices by ensuring consistent light emission across the light guide plate.
Implementation Method 1
A diffusion layer comprising a transparent adhesive and light diffusion particles, including organic and inorganic particles, is applied to the light emitting surface of LEDs to increase the distribution angle of light
Implementation Method 2
a ratio of a refractive index of the transparent adhesive to a refractive index of the organic light diffusion particles ranges from 1.05 to 1.08; a ratio of a refractive index of the transparent adhesive to a refractive index of the inorganic light diffusion particles ranges from 0.93 to 0.98
Data Source
AI summary
A backlight module and a liquid crystal display device are provided. By forming a diffusion layer on a light emitting surface of each of a plurality of light emitting diodes (LEDs), a light shadow and a LED light path generated by misalignment between the LEDs and a light guide plate and deformation of a reflective sheet can be effectively avoided. The backlight module emits light of uniform brightness to improve display performance of the liquid crystal display device.