LED Backlight Double-Sided PCB Wiring for Uniform Illumination
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Solution Overview
Problem
Conventional LCD backlights using LEDs for local dimming face complexity in wiring configurations due to the need for multiple lead patterns and connectors, which can block light and cause darkness in certain areas of the panel.
Innovation Solution
A double-sided printed circuit board with conductive vias and lead patterns on both surfaces is used to connect LEDs directly to driving circuit connectors, eliminating the need for module connectors and simplifying the wiring configuration, while also incorporating heat radiating vias and insulating pads for improved heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If module connectors and conductive lines are disposed above the LEDs to electrically connect LED modules, then electrical connection between modules is achieved, but light is blocked causing darkness in corresponding LCD panel areas
Solution Approach 1:
The patent moves the conductive lines from the top surface (above LEDs) to the bottom surface of the PCB, utilizing the third dimension (vertical space) to resolve the conflict between electrical connection and light transmission. This allows light to pass unobstructed while maintaining electrical connectivity through conductive vias that penetrate the PCB.
Solution Approach 2:
Conductive vias serve as intermediaries to transfer electrical signals from the bottom surface lead patterns to the top surface connection points, enabling electrical connection without requiring physical conductive lines above the LEDs that would block light.
2Adaptability or versatility
If multiple lead patterns and module connectors are used to connect LEDs to driving circuits, then local dimming functionality is achieved, but wiring configuration becomes complex
Solution Approach 1:
The patent utilizes the bottom surface of the PCB as an additional dimension for routing conductive lines, eliminating the need for complex overhead wiring and module connectors. This simplifies the overall wiring configuration while preserving local dimming capability.
Solution Approach 2:
The patent integrates the connection functions of multiple separate lead patterns and module connectors into a unified bottom-surface wiring system with conductive vias, reducing the total number of components and simplifying the wiring configuration.
3Reliability
If conventional wiring structures with connectors are used, then electrical connection is achieved, but light blocking causes non-uniform illumination across the panel
Solution Approach 1:
By relocating all conductive elements to the bottom surface of the PCB and using conductive vias for vertical connection, the patent eliminates light-blocking structures from the light path area, ensuring uniform illumination across the entire LCD panel while maintaining reliable electrical connections.
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 simplifies the connection structure, prevents light blocking, and enhances heat radiation, allowing for more efficient local dimming and improved illumination uniformity across the LCD panel without the need for additional connectors.
Implementation Method 1
a plurality of second lead patterns formed on an underside surface of the double-sided printed circuit board to electrically connect the first lead patterns with the connectors through the conductive vias
Implementation Method 2
incorporating heat radiating vias and insulating pads for improved heat management
Data Source
AI summary
In an LCD backlight unit using a light emitting diode, a double-sided printed circuit board includes a plurality of divided areas and conductive vias. A plurality of light emitting diodes are disposed on a top surface of the double-sided printed circuit board. A plurality of driving circuit connectors are disposed at a portion of the double-sided printed circuit board. A plurality of first lead patterns are formed on the top surface of the printed circuit board, each of the first lead patterns electrically connecting the light emitting diodes in each of the divided areas with one another. Also, a plurality of second lead patterns are formed on an underside surface of the double-sided printed circuit board to electrically connect the first lead patterns with the connectors through the conductive vias.