Display Device Driving Transistor Sensing Timing
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Solution Overview
Problem
In organic light-emitting display devices, luminance deviations among subpixels occur due to changes in transistor characteristics over time, leading to image quality degradation, despite existing solutions for sensing and compensating these deviations, which can be affected by sensing errors and data voltage changes during the blank and sensing periods.
Innovation Solution
A method and device that minimize data voltage changes between the start of the blank period and the sensing period of driving transistors, using a compensation circuit to sense and adjust transistor characteristics, thereby reducing sensing deviations and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If real-time sensing of driving transistor characteristics is performed during image driving, then image quality can be maintained through compensation, but sensing deviations occur due to data voltage changes between blank period start and sensing start
Solution Approach 1:
The patent applies preliminary action by performing sensing of driving transistor characteristics at a specific timing point (at the start of the blank period or before data voltage changes occur) rather than during the image driving period. This preliminary sensing ensures that the sensed characteristics reflect the actual transistor state before any voltage-induced deviations occur, thereby maintaining both reliability through compensation and measurement precision by avoiding sensing errors caused by data voltage changes.
2Reliability
If sensing is performed during the blank period, then compensation can be applied, but data voltage changes between blank period start and sensing start cause sensing deviations
Solution Approach 1:
The patent performs the sensing operation at the very beginning of the blank period or even during the image driving period before the blank period officially starts, capturing transistor characteristics before any blank period voltage changes occur. This preliminary timing ensures that the sensed values are accurate and free from the deviations caused by subsequent data voltage changes during the blank period, while still enabling timely compensation.
Solution Approach 2:
The patent implements a feedback mechanism where the sensed transistor characteristics (threshold voltage, mobility) are used to generate compensation values that are applied to correct luminance deviations in subsequent image driving. The feedback loop continuously monitors and compensates for transistor degradation and variations, maintaining image quality despite device aging and manufacturing variations.
3Ease of operation
If data voltage is allowed to change freely during blank period, then normal operation is maintained, but luminance deviations occur among subpixels due to sensing errors
Solution Approach 1:
The patent performs sensing of driving transistor characteristics at a timing point before data voltage changes occur during the blank period (either at the very start of the blank period or during the image driving period). This preliminary sensing captures accurate transistor characteristics free from voltage-induced deviations, enabling proper compensation that maintains luminance uniformity across all subpixels while allowing normal data voltage operations to proceed.
Data Source
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AI summary
A display device (100) and a method of driving the same. Characteristics of driving transistors disposed in subpixels (SP) of a display panel (110) are sensed and compensated for, thereby improving the image quality of the organic light-emitting display device. Changes in a data voltage (Vdata) between a point in time at which a blank period (BP) starts and a period in which the sensing of the driving transistors starts are minimized, thereby reducing deviations in the sensing of the characteristics of the driving transistors.