Backlight Unit Barrier Layer for Thin Local-Dimming Displays
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Solution Overview
Problem
Direct-light-type backlight units for liquid crystal display devices face challenges in reducing thickness due to the placement of light sources under the liquid crystal panel, which increases the overall thickness and limits local dimming capabilities.
Innovation Solution
A backlight unit design featuring a substrate with light-emitting chips, a barrier layer with slits between the electrode pads and solder, and a reflective layer, which reduces the contact area between the solder and electrode pads, allowing for thinner construction and facilitating rework processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light sources are disposed under the liquid crystal panel in a direct-light-type backlight unit, then local dimming capability and light uniformity are improved, but the thickness of the backlight unit increases
Solution Approach 1:
The patent extracts the light source from the traditional backlight unit structure and integrates it directly into the display panel's TFT substrate. By mounting light-emitting chips on the front surface of the TFT substrate and connecting them via conductive paste, the invention eliminates the need for a separate backlight unit, thereby achieving local dimming capability while reducing overall thickness
Solution Approach 2:
The invention merges the light source function with the display panel structure itself. The TFT substrate serves dual purposes as both the display control layer and the light-emitting platform. By combining these functions into a single integrated structure, the patent achieves both thinness and local dimming capability without requiring separate backlight components
2Illumination intensity
If light sources are disposed under the liquid crystal panel, then light uniformity and brightness are improved, but the thickness of the backlight unit increases
Solution Approach 1:
The patent removes the traditional backlight unit entirely and extracts the light generation function to be performed directly by chips mounted on the TFT substrate. This extraction allows light to be generated at the precise location where it is needed, improving uniformity while eliminating the thickness penalty of a separate backlight assembly
Solution Approach 2:
The invention applies local quality by enabling independent control of light emission at different regions of the display panel. Each light-emitting chip can be controlled individually or in groups, allowing localized adjustment of brightness and uniformity without affecting the entire panel, while maintaining a thin profile
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 achieves a reduction in backlight unit thickness and enables effective local dimming, improving contrast ratio and power efficiency while maintaining reliable chip mounting and rework capabilities.
Implementation Method 1
a barrier layer disposed between the electrode pad and the solder, the barrier layer having at least one slit
Implementation Method 2
a plurality of light-emitting chips mounted on the substrate
Data Source
AI summary
A display device including a backlight unit that includes a barrier layer disposed between a light-emitting chip and an electrode pad to reduce the contact area between a solder and the electrode pad due to the barrier layer, so that a portion of the electrode pad overlapping with the barrier layer is left behind without being diffused into the solder, and rework can be performed on a process of mounting the light-emitting chip.