OLED Driving TFT Compensation via Periodic Line Sensing
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Solution Overview
Problem
Existing organic light emitting displays experience luminance deviation due to variations in electrical characteristics of driving TFTs, leading to visual perception of 'line dim' issues, as real-time sensing is performed only on one display line per image frame, causing uneven emission duty and prolonged generation cycle of luminance deviation.
Innovation Solution
The solution involves a timing controller and driving circuit unit that modulates digital video data to compensate for changes in TFT characteristics, performing real-time sensing and applying image display data sequentially to other pixels during the image display period, ensuring uniform emission duty from luminance recovery data across all display lines, regardless of location, thereby reducing visual perception of 'line dim'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If real-time sensing is performed only on one display line per image frame, then the sensing operation can be completed within the available time, but the emission duty becomes uneven across display lines causing luminance deviation and visible 'line dim' issues
Solution Approach 1:
The patent divides the display panel into multiple sensing target display lines that are selected alternately across different image frames. Instead of sensing only one line per frame, multiple lines are segmented across time, with each line being sensed in alternating frames. This segmentation allows the emission duty to be uniformized across all sensing target lines by ensuring they all undergo the same sensing and recovery process periodically, thereby eliminating the luminance deviation and 'line dim' issues while keeping the sensing operation time manageable.
2Illumination intensity
If sensing is performed on multiple display lines per image frame, then luminance uniformity can be improved, but the sensing operation cannot be completed within the available time
Solution Approach 1:
The patent implements periodic sensing by selecting sensing target display lines alternately across different image frames. Each display line is designated as a sensing target in alternating frames, allowing the sensing operation to be completed within the time constraints of each frame while ensuring that all lines receive uniform treatment over time. This periodic approach distributes the sensing load across multiple frames rather than requiring all lines to be sensed simultaneously in one frame.
3Measurement precision
If the generation cycle of luminance deviation is prolonged, then the compensation operation can be performed accurately, but the luminance deviation becomes visible as 'line dim' to users
Solution Approach 1:
The patent dynamically adjusts the selection of sensing target display lines across different image frames. By making the sensing target selection dynamic and alternating through multiple lines over time, the system maintains accurate compensation operations while reducing the generation cycle of luminance deviation. This dynamic approach ensures that no single line suffers from prolonged deviation, as each line is periodically selected for sensing and recovery, making the luminance deviation imperceptible to users while preserving compensation accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the visibility of luminance deviation as 'line dim' by shortening the generation cycle of luminance deviation, making it imperceptible even at high-speed drives, such as 1/120 seconds or faster, by uniformly applying emission duty from luminance recovery data.
Implementation Method 1
When a driving voltage is applied to the anode electrode and the cathode electrode, holes passing through the hole transport layer HTL and electrons passing through the electron transport layer ETL move to the light emitting layer EML and form excitons. As a result, the light emitting layer EML generates visible light.
Data Source
AI summary
An organic light emitting display includes a display panel, on which a plurality of pixels each including an organic light emitting diode and a driving thin film transistor (TFT) controlling a current flowing in the organic light emitting diode are disposed, a timing controller configured to modulate input digital video data to compensate for changes in electric characteristic of the driving TFT, and a driving circuit unit configured to changes in electric characteristic of the driving TFT of each of specific pixels of the plurality of pixels in an image display period of each image frame and sequentially apply image display data to remaining pixels except the specific pixels along one direction in the image display period.