Backlight Module Edge Light Uniformity via Low Reflective Portions
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Solution Overview
Problem
Conventional backlight modules for LCDs face challenges in achieving uniform light distribution and reducing light leakage, particularly at the edges where there are no adjacent blocks to complement light, resulting in bright and dark regions.
Innovation Solution
A backlight module design featuring a carrier plate with outer light sources along its side edge, low reflective portions between the light sources and the edge, and a modulation film with varying light emitting structures to distribute light uniformly, including projection areas with lower normalized transmission ratios to absorb excess light and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective film with multiple blocks and holes is used to disperse light, then light sources can be dispersed through holes, but at the edge of the reflective film where there are no adjacent blocks to complement light, bright and dark regions appear causing poor light uniformity
Solution Approach 1:
The patent introduces a low reflective portion at the edge of the reflective film specifically to address the light uniformity problem at the edge. This local modification changes the reflectance property in the edge region (second reflectance lower than first reflectance in central region), allowing the edge area to absorb or block excess light that would otherwise create bright regions, thereby achieving uniform light distribution across the entire display area.
2Length of stationary object
If the backlight module thickness is reduced to achieve thinner LCD, then the overall device becomes thinner, but the backlight module requires a light mixing space which conflicts with thinning requirements
Solution Approach 1:
The patent modifies the reflectance parameter of the reflective film by introducing regions with different reflectance values (first reflectance in central region, second reflectance lower than first in edge region). This parameter change allows the light mixing process to be more efficient within a thinner structure, as the differentiated reflectance regions guide light paths more effectively, achieving both thinness and adequate light mixing.
3Area of stationary object
If outer light sources are placed along the side edge to provide edge lighting, then light coverage is improved, but light leakage occurs at the edge regions without proper control
Solution Approach 1:
The patent applies local quality by creating a low reflective portion specifically at the edge region where outer light sources are positioned. This local modification with lower reflectance (second reflectance) controls the light behavior at the edge, preventing light leakage by absorbing or blocking excess light that escapes from the outer light sources, while maintaining broad light coverage through the outer light source arrangement.
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 design enhances light uniformity and reduces light leakage by strategically placing low reflective portions and adjusting the normalized transmission ratio on the modulation film, ensuring consistent brightness across the display.
Implementation Method 1
The low reflective portions have a second reflectance less than the first reflectance
Implementation Method 2
The modulation film distributes the light generated by the light sources to emit through the light emitting structures at different positions
Data Source
AI summary
A backlight module including a carrier plate, a plurality of light sources, at least one low reflective portion, and a modulation film is provided. The carrier plate has a carrier surface carrying the light sources while the low reflective portion is disposed on the carrier surface between an outer light source and a side edge of the carrier plate. The reflectance of the low reflective portion is less than that of the carrier surface. The modulation film is disposed above the light sources while the low reflective portion has a projection area on the modulation film. The projection area has a lower normalized transmission ratio comparing to adjacent areas along an extending direction of the side edge of the carrier plate.