Display Device Sensing Transistor Deterioration
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Solution Overview
Problem
In organic light emitting display devices, luminance differences between pixels due to transistor deterioration can cause stains, and existing solutions fail to effectively sense and compensate for this deterioration during image display periods without prolonging power-off periods or affecting user recognition.
Innovation Solution
A display device with a sensing unit outside the display unit that senses and compensates for driving transistor deterioration during power-off, power-on, and image display periods using a combination of scan drivers, multiplexers, and operational amplifiers, allowing for short sensing periods and efficient compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensing and compensation is performed during image display period, then display quality is maintained without stains, but sensing period duration increases
Solution Approach 1:
The patent performs sensing operations during power-off periods and vertical blanking intervals before the image display period begins. By conducting threshold voltage sensing and compensation in advance (during periods when the display is not actively showing images), the system maintains display quality without extending the actual image display time, thus resolving the contradiction between maintaining reliability and minimizing time loss.
Solution Approach 2:
The patent implements periodic sensing during vertical blanking intervals that occur regularly during display operation. These periodic sensing windows allow the system to continuously monitor and compensate for transistor deterioration without interrupting the main image display, effectively utilizing otherwise wasted time periods to maintain display quality while minimizing impact on visible display time.
2Measurement precision
If sensing unit is integrated within display unit, then sensing precision is improved, but device complexity increases
Solution Approach 1:
The patent separates the sensing unit from the display unit, creating independent sensing and display modules. The sensing unit includes dedicated sensing lines, scan drivers, and compensation circuits that operate separately from the main display pixel structures. This segmentation allows each unit to be optimized independently - the sensing unit for precision and the display unit for visual output - while reducing overall device complexity through modular design.
Solution Approach 2:
The patent introduces dedicated sensing lines as intermediary elements that connect the sensing unit to the pixel circuits without interfering with the normal display function. These sensing lines serve as mediators that allow threshold voltage measurement to occur through separate pathways, enabling precise sensing while keeping the display unit structure simple and unchanged.
3Measurement precision
If power-off period is extended for sensing, then sensing accuracy is improved, but productivity decreases
Solution Approach 1:
The patent maintains continuous sensing capability by utilizing vertical blanking intervals that occur during normal display operation. Instead of requiring extended power-off periods, the system continuously performs sensing operations during these brief intervals, ensuring that useful sensing action never stops while the display remains active. This continuity maintains sensing accuracy without reducing display productivity.
Solution Approach 2:
The patent performs sensing operations rapidly during vertical blanking intervals by applying sensing voltages and measuring threshold voltages in compressed time windows. The sensing unit rushes through the sensing process during these brief periods, obtaining accurate measurements without requiring prolonged power-off states, thus maintaining both sensing accuracy and display efficiency.
Data Source
AI summary
A display device includes a display unit including a plurality of pixels and a sensing unit disposed outside the display unit, where the sensing unit senses deterioration information of a driving transistor in each of the pixels through a plurality of sensing lines, and compensates for deterioration of the driving transistor. the sensing unit senses the deterioration information during a first sensing period, and the first sensing period is included in each of a power-off period in which power for the display device to display an image is not supplied, a power-on period in which the display device is turned on, and an image display period in which the image is continuously displayed after the display device is turned on.