Backlight Module Vias for Mini-LED Brightness Uniformity
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Solution Overview
Problem
The IR drop in Mini-LED backlight modules causes current differences and brightness mura due to voltage variations across the backlight module, leading to uneven brightness.
Innovation Solution
A backlight module design featuring a substrate with vias of varying sizes that correlate with the brightness of light emitting devices, a reflective layer, and an optical film layer to enhance uniformity, where the areas of the vias close to the electric current input side are larger than those farther away, and the light emitting devices include red, green, and blue LEDs arranged in units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If voltage driving is used for Mini-LED backlight, then lighting control is achieved, but IR drop causes current differences and brightness mura
Solution Approach 1:
The patent applies local quality by varying the via area sizes at different locations on the substrate. Vias closer to the power source have larger areas to handle higher current, while vias farther away have smaller areas. This localized adjustment compensates for IR drop effects and achieves uniform brightness across the backlight module.
Solution Approach 2:
The patent changes the physical parameter of via area to compensate for voltage drops. By adjusting the via area parameter based on distance from the power source, the current distribution is optimized to maintain consistent brightness across different regions of the backlight module.
2Ease of manufacture
If uniform via sizes are used, then manufacturing is simplified, but brightness mura occurs due to IR drop
Solution Approach 1:
The patent implements local quality by designing different via area sizes for different regions. This requires modified manufacturing processes to create variable via sizes, but it resolves the brightness uniformity issue caused by IR drop in voltage-driven Mini-LED backlights.
3Reliability
If larger via areas are used near power source, then current distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent systematically varies the via area parameter based on position relative to the power source. This controlled parameter change improves current distribution uniformity while maintaining a relatively simple design rule that can be implemented with standard manufacturing techniques.
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 reduces brightness differences across the backlight module, enhancing uniformity and reducing parasitic light, thereby improving the overall brightness and color saturation of the display panel.
Implementation Method 1
a light emitting device layer disposed on the reflective layer, wherein the light emitting device layer comprises a plurality of light emitting devices electrically connected with the pads though the vias
Implementation Method 2
a reflective layer disposed on the substrate, wherein vias which expose the pads are defined by the reflective layer
Data Source
AI summary
The embodiments of the present application provided a backlight module and a display panel. By disposing a reflective layer on the substrate and disposing vias, whose areas gradually decrease from the side close to an electric current input side to the side away from the electric current input side, on the reflective layer, the backlight module reduces the brightness of a light emitting device layer close to the electric current input side and increase the brightness of the light emitting device layer away from the electric current input side. Thus the brightness of both sides of the light emitting devise layer is uniform, and thus the backlight uniformity of the backlight module is increased.