LED Panel Driving Device Pre-Charge Scan Lines
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Solution Overview
Problem
Conventional passive matrix (PM) light-emitting diode (LED) panels face erroneous driving issues such as afterimages due to improper driving methods.
Innovation Solution
The proposed solution involves a driving device with a source driver and a scan driver. The source driver outputs driving currents to data lines during scan line periods, while the scan driver applies enable and pre-charge voltages to scan lines, managing short-circuited LEDs by setting them as electrically floating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional driving methods are used in PM LED panels, then the panel can be driven, but erroneous driving problems such as afterimages occur
Solution Approach 1:
The patent applies preliminary action by pre-charging scan lines before they are activated. Specifically, during the inactive period before a scan line becomes active, the scan driver pre-charges the scan line to a predetermined voltage level. This preliminary charging ensures that when the scan line becomes active, there is no sudden voltage change that could cause afterimages, thus improving driving accuracy and eliminating the harmful afterimage effect.
2Duration of action of stationary object
If scan lines are continuously activated, then display continuity is maintained, but reverse bias voltage damage occurs to LED circuits
Solution Approach 1:
The patent implements periodic action by dividing the operation into active periods and inactive periods. During inactive periods, scan lines are pre-charged to a safe voltage level before becoming active again. This periodic pre-charging ensures that LED circuits never experience dangerous reverse bias voltage, while maintaining continuous display operation. The cycle of active display followed by pre-charge preparation prevents damage while ensuring continuity.
3Productivity
If driving current is applied to all scan lines, then full panel operation is achieved, but current shunting occurs through short-circuited LEDs
Solution Approach 1:
The patent applies local quality by treating scan lines differently based on their connection status. When a short-circuited LED is detected in a particular scan line, the scan driver identifies this specific location and applies a different voltage level to that scan line compared to normal scan lines. This localized adjustment prevents driving current from shunting through the short-circuited LED, while other scan lines continue to operate normally, maintaining overall panel productivity.
Data Source
AI summary
A light-emitting diode (LED) panel and a driving device therefore is provided. The driving device includes a source driver and a scan driver. The source driver is coupled to a plurality of data lines disposed in the LED panel. The source driver outputs driving currents to the data lines in any one of a plurality of scan line periods, to drive an LED array of the LED panel. The scan driver is coupled to a plurality of scan lines disposed in the LED panel, wherein the scan driver scans the scan lines during the plurality of scan line periods. In an active period of any one of the scan line periods, the scan driver applies an enable voltage to a current scan line among the scan lines, and the scan driver applies a pre-charge voltage to other scan line among the scan lines.