Common-Anode LED Lamp Bead Circuit Against Caterpillar Defects
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Solution Overview
Problem
Existing LED display screens suffer from the 'caterpillar phenomenon' due to short circuits between negative electrodes of green and blue LED chips, leading to display failures and inefficient maintenance, which affects display quality and efficiency.
Innovation Solution
Reconfigure the LED chip connections such that green and blue LED chips share a common positive pad, preventing short circuits between negative electrodes, and utilize separate drive units to regulate voltage in case of failures, allowing positive electrode-negative electrode short circuits to occur instead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If green and blue LED chips are connected to separate negative pads, then each chip can be independently controlled, but short circuits between negative electrodes occur causing caterpillar phenomenon
Solution Approach 1:
The patent merges the negative electrode connections of green and blue LED chips to a common negative pad, eliminating the separate negative pads that caused short circuit issues. This combining approach prevents the caterpillar phenomenon while maintaining display functionality through the common anode connection structure.
Solution Approach 2:
The patent inverts the traditional common cathode connection mode to a common anode connection mode. By making the anode common and connecting each color chip's cathode to separate control circuits, the patent achieves both independent control capability and elimination of negative electrode short circuits.
2Reliability
If common anode connection mode is used, then short circuits between negative electrodes are prevented, but maintenance efficiency is reduced due to complex voltage regulation requirements
Solution Approach 1:
The patent segments the control system into independent column drive units, each capable of independently regulating voltage for different color chips. This segmentation allows faulty chips to be identified and repaired without affecting other columns, improving maintenance efficiency despite the common anode configuration.
Solution Approach 2:
The patent implements dynamic voltage regulation through column drive units that can adjust voltage parameters for different color chips and columns. This parameter control capability enables efficient fault isolation and repair by regulating voltage to identify and isolate problematic chips without manual testing.
3Ease of operation
If separate negative pads are used for each LED chip, then voltage can be regulated through column driver chip, but short circuits occur leading to entire column display failure
Solution Approach 1:
The patent merges the negative electrode connections to a common negative pad, which fundamentally prevents short circuits between different color chips. This merging eliminates the root cause of column-wide failures while the common anode structure preserves voltage regulation capability through the control circuits.
Solution Approach 2:
The patent designs the common anode connection structure as a preventive measure against short circuits. By anticipating the short circuit problem with separate negative pads, the patent proactively structures the circuit to prevent this failure mode before it can occur, ensuring column display continuity.
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
Prevents negative electrode short circuits, maintains display quality by controlling voltage, and facilitates efficient maintenance by quickly identifying and replacing faulty LED chips.
Implementation Method 1
a red-light LED chip 21, a green-light LED chip 22, and a blue-light LED chip 23
Implementation Method 2
positive electrode and a negative electrode of the red-light LED chip are located on a front side and a back side of the red-light LED chip respectively
Data Source
AI summary
Disclosed in the present invention are a full-color lamp bead, drive circuit, lamp panel and display module for an LED display screen. A full-color lamp bead unit of the full-color lamp bead comprises a red-light LED chip, a green-light LED chip, a blue-light LED chip, and a common positive pad, a red-light chip negative pad, a green-light chip negative pad and a blue-light chip negative pad, which are formed on a substrate, wherein a negative electrode of the red-light LED chip is connected to the red-light chip negative pad, and a positive electrode of the red-light LED chip is connected to the common positive pad; the green-light LED chip and the blue-light LED chip are fixed on the common positive pad; positive electrodes of the green-light LED chip and the blue-light LED chip are connected to the common positive pad; and negative electrodes of the green-light LED chip and the blue-light LED chip are respectively connected to the green-light chip negative pad and the blue-light chip negative pad. By means of the full-color lamp bead of the present invention, the phenomenon of a short circuit between negative electrodes does not occur, such that the “caterpillar phenomenon” can be prevented from occurring in an LED display screen.