Curved Full-Array LED Backlight Using Rigid PCB Dimming Bars
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Solution Overview
Problem
Current solutions for implementing full-array local dimming technology in curved LCDs are hindered by the high cost and mechanical limitations of flexible PCBs, which struggle to maintain a one-dimensional curved surface while supporting electronic components, leading to difficulties in achieving high contrast ratios and image quality.
Innovation Solution
A curved full-array LED light panel utilizing non-flexible bar-shaped PCBs with dimming-zone circuits and a flexible reflective sheet, where LEDs are exposed through openings, allowing for independent luminance control and forming a curved surface without the mechanical weaknesses of flexible PCBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a flexible PCB is used to implement full-array local dimming in a curved LCD, then the backlight module can be formed into a curved surface, but the mechanical strength and rigidity are insufficient to support electronic components, and the cost is very high
Solution Approach 1:
The patent divides the backlight module into multiple bar-shaped PCB segments, each independently structured with LEDs arranged in arrays. These segmented bars are then bent to form a curved surface, allowing each segment to maintain its structural integrity while collectively forming the desired curved shape. This segmentation resolves the contradiction by enabling curvature without compromising the mechanical strength of individual PCB segments.
2Shape
If a flexible PCB is used to implement full-array local dimming in a curved LCD, then the backlight module can be formed into a curved surface, but the manufacturing cost becomes very high
Solution Approach 1:
The backlight module is segmented into multiple bar-shaped PCB units that can be manufactured independently using standard rigid PCB fabrication processes. These segments are then assembled to form the curved surface, avoiding the need for expensive flexible PCB materials and processes while achieving the desired curved shape.
Solution Approach 2:
The patent uses a flexible reflective sheet as the substrate to which the rigid bar-shaped PCB segments are attached. This flexible sheet enables the overall curved configuration while the rigid PCB segments maintain their structural integrity and can be manufactured using cost-effective rigid PCB processes.
3Manufacturing precision
If more LED dimming zones are specified to improve contrast ratio, then the image contrast ratio increases, but the surface area of each LED dimming zone becomes smaller and the complexity increases
Solution Approach 1:
The patent divides the LED array into multiple bar-shaped PCB segments, with each segment containing multiple LED dimming zones. This hierarchical segmentation allows for a large total number of dimming zones across the entire curved surface while maintaining manageable complexity within each individual bar segment. Each bar can be independently controlled and manufactured.
Solution Approach 2:
The patent arranges LEDs in a two-dimensional array across multiple bar-shaped segments that are curved to form a three-dimensional curved surface. This dimensional arrangement allows for numerous dimming zones to be distributed across the curved surface area, increasing the total number of controllable zones without excessively increasing the complexity of individual control circuits.
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 solution enables efficient local dimming in curved LCDs with improved contrast ratios and image quality while reducing manufacturing costs, as non-flexible PCBs provide sufficient mechanical strength and lower costs compared to flexible PCBs.
Implementation Method 1
Along a width direction of the flexible reflective sheet, the sheet-rear side of the flexible reflective sheet is deformed toward the sheet-front side of the flexible reflective sheet to form a curved reflective surface
Implementation Method 2
a plurality of LEDs disposed on the front side of the non-flexible PCB
Implementation Method 3
each dimming-zone circuit is electrically connected with at least one LED so as to adjust the luminous intensity
Data Source
AI summary
A curved full-array LED light panel, a curved backlight module including the curved full-array LED light panel, and a curved LCD including the backlight module are disclosed. The curved full-array LED light panel includes a flexible reflective sheet and a plurality of LED light bars wherein a plurality of LEDs are disposed. The plurality of LED light bars are attached to a sheet-rear side of the flexible reflective sheet alone a direction parallel to the height direction of the full-array LED light panel, and the plurality of LEDs disposed on the LED light bars are exposed from a plurality of openings of the flexible reflective sheet toward an LCD panel. Along a direction parallel to the width direction of the full-array LED light panel, the flexible reflective sheet is deformed to form a curved reflective surface. Each of the LED light bars further comprises a bar-shaped PCB, and a plurality of LED dimming-zone circuits are disposed on the bar-shaped PCB. Full-array local dimming of the curved full-array LED light panel can be achieved by controlling the electric current of the LED dimming-zone circuits.