OLED Display Short-Circuit Protection via Reverse Voltage Detection
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Solution Overview
Problem
Organic light emitting display devices face damage due to overcurrent caused by short-circuits between power lines, which can lead to burning of organic light emitting diodes and panel damage, as existing technologies lack effective detection and control mechanisms to prevent such occurrences.
Innovation Solution
An organic light emitting display device with a short-circuit-sensing circuit that detects abnormal currents and controls the DC-DC converter to block driving power, utilizing a DC-DC converter to apply power sources with varying voltage levels and a reverse voltage application period to identify and prevent short-circuits between power lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC-DC converter outputs power sources to pixels via power lines, then the display device can operate with proper power supply, but short-circuit between power lines can cause overcurrent and damage to OLEDs
Solution Approach 1:
The patent applies preliminary action by performing short-circuit detection during a reverse voltage application period before normal operation. The sensing circuit detects abnormal currents when reverse voltage is applied to the power lines, identifying potential short-circuits before they can cause damage during normal display operation. This preventive detection approach allows the system to block power supply proactively rather than reacting after damage occurs.
Solution Approach 2:
The patent introduces an intermediary sensing circuit that mediates between the DC-DC converter and the power lines. This sensing circuit includes current sensing components that monitor the power lines for abnormal conditions. The intermediary circuit processes the sensed signals and controls the DC-DC converter to block power supply when short-circuits are detected, acting as a protective buffer between the power source and the vulnerable OLEDs.
2Measurement precision
If voltage levels of power sources are changed in a frame period including reverse voltage application period, then short-circuits can be detected, but the operation becomes more complex
Solution Approach 1:
The patent implements periodic action by incorporating a reverse voltage application period within the frame period for regular short-circuit detection. During this specific time window, the voltage levels of power sources are switched to reverse polarity, creating a periodic detection cycle. This periodic reverse voltage application allows the sensing circuit to regularly monitor for short-circuits without interfering with normal display operation during other parts of the frame period.
Solution Approach 2:
The patent applies preliminary anti-action by using reverse voltage application to create conditions that reveal potential short-circuits. The reverse voltage temporarily opposes the normal current flow direction, which causes abnormal current patterns to manifest in detectable ways during this brief period. This preliminary anti-action approach allows the system to identify vulnerabilities before they become problematic during normal forward voltage operation.
Data Source
AI summary
An organic light emitting display device includes a display unit including pixels coupled to scan lines and data lines, first and second power lines coupled to the pixels, a DC-DC converter configured to output first and second power sources to the pixels via the first and second power lines, respectively, and a short-circuit-sensing circuit configured to detect whether a short-circuit between the first and second power lines occurs, and configured to control an operation of the DC-DC converter when the short-circuit is detected, wherein voltage levels of the first and second power sources are configured to be changed in a frame period, the frame period including a reverse voltage application period in which the voltage level of the second power source is higher than that of the first power source.