OLED Display Random Scan Timing for Luminance Compensation
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Solution Overview
Problem
Organic light-emitting display devices face challenges in maintaining display quality due to the deterioration of organic light-emitting elements over time, particularly when using digital driving methods, which can lead to luminance drops during sensing current application.
Innovation Solution
The implementation of a random scanning method that time-divides each frame into sub-frames with varying emission periods, where scan signals are applied to multiple scan lines at intervals, and sensing voltages are used to detect deteriorated elements while minimizing luminance drops by rescanning and applying data voltages to affected pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing current is applied to detect deteriorated organic light-emitting elements during digital driving, then detection accuracy is improved, but luminance of the display temporarily decreases
Solution Approach 1:
The patent applies sensing current during low-bit sequence sub-frames (earlier in the frame period) before the high-bit sequence sub-frames. This preliminary detection allows the system to identify deteriorated elements before they would cause significant luminance drops during the more visually critical high-bit sub-frames, thus maintaining both detection accuracy and display luminance quality.
Solution Approach 2:
The patent dynamically adjusts the timing and positioning of sensing current application based on the bit sequence of sub-frames. By adapting when sensing occurs relative to the visual importance of each sub-frame, the system optimizes the balance between detection needs and luminance maintenance, making the sensing operation less intrusive to overall display quality.
2Measurement precision
If sensing current is applied during higher-bit sequence sub-frames, then detection precision is maintained, but luminance drop becomes more apparent
Solution Approach 1:
The patent performs sensing operations during low-bit sequence sub-frames before the high-bit sequence sub-frames occur. This preliminary action allows detection to be completed when the visual impact of any luminance drop is minimal, preventing apparent luminance drops during the more visually significant high-bit sub-frames while maintaining detection precision.
Solution Approach 2:
The patent implements periodic sensing operations at specific intervals within the frame structure, specifically during low-bit sub-frames. This periodic timing strategy ensures that sensing occurs at optimal moments when luminance drops are least noticeable, creating a rhythm of detection that balances measurement needs with visual quality requirements.
Data Source
AI summary
An organic light-emitting display device displays a grayscale level by time-dividing each frame into N sub-frames, the organic light-emitting display device including: a plurality of pixels arranged in a matrix; a plurality of scan lines to be provided with a plurality of scan signals to turn on the plurality of pixels; and a plurality of data lines to be selectively provided with a plurality of data voltages or a plurality of sensing voltages to be applied to a number of the pixels that are turned on by each of the plurality of scan signals, wherein the scan signals are provided to N scan lines (where N is a natural number greater than 1) that are randomly selected from among the plurality of scan lines at intervals of a sub-horizontal period.