Display Device Defect Detection Using Reference Voltage Sensing
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Solution Overview
Problem
Display devices utilizing self-emitting organic light-emitting diodes (OLEDs) face defects such as open or short circuits in signal lines, leading to the panel burnt phenomenon, which can result in abnormal operation and even fires, necessitating proactive detection and accurate identification of defects to prevent damage.
Innovation Solution
A display device and driving method that includes a sensing circuit to detect defects by comparing voltages during reference voltage supply and interruption periods, using switches to control voltage lines and determine defects based on threshold values, allowing for real-time detection and reduced processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time sensing processes are performed during display driving to detect panel burnt defects, then detection accuracy is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary voltage sensing during the blank time period before the next frame is displayed. By utilizing this idle time for defect detection, the system achieves real-time monitoring without extending the overall display cycle time, thus resolving the contradiction between detection accuracy and processing time.
Solution Approach 2:
The sensing circuit periodically detects voltage levels during each blank time interval in the display refresh cycle. This periodic sensing approach ensures continuous monitoring capability while maintaining the normal display timing, allowing accurate defect detection without adding processing time overhead.
2Loss of time
If voltage sensing is performed during blank time only, then detection time is reduced, but detection opportunities are limited
Solution Approach 1:
The sensing circuit is designed to perform multiple functions: it senses voltage during blank time for rapid defect detection, and can also operate during active display periods for comprehensive monitoring. This multi-functional design ensures both fast response time and reliable detection coverage across all operating conditions.
3Measurement precision
If reference voltage lines are directly used for defect detection, then detection accuracy is improved, but circuit complexity increases
Solution Approach 1:
The reference voltage lines serve dual purposes: they provide necessary reference voltages for the OLED display operation and simultaneously function as sensing pathways for defect detection. By making these existing lines multi-functional, the system achieves high detection accuracy without adding separate sensing circuitry, thus avoiding increased circuit complexity.
Solution Approach 2:
The reference voltage lines self-serve the dual function of power/reference provision and defect sensing. The same conductive pathways that carry reference voltages are utilized by the sensing circuit to detect voltage drops indicating panel burnt defects, eliminating the need for dedicated sensing lines and reducing overall circuit complexity.
Data Source
AI summary
Embodiments relate to display devices and driving methods thereof. A display device includes a display panel including a sub-pixel arranged thereon and configured to display an image, a power controller configured to supply a reference voltage to the sub-pixel, a sensing circuit configured to sense a voltage of the sub-pixel during a blank time within a frame during the display driving of the image, and a timing controller configured to detect a defect of the display panel based on the voltage sensed during the display driving.