OLED Display Substrate Multiplexer Circuit for Brightness Uniformity
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Solution Overview
Problem
The existing OLED substrates face issues with non-uniform threshold voltages of driving transistors, leading to varying brightness of OLEDs and a reduced display effect, due to manufacturing tolerances and electrical characteristic drifts, and the current driving methods do not effectively compensate for these differences, especially as resolution increases.
Innovation Solution
The proposed solution involves a display substrate with a specific arrangement of gate and data lines, coupled with multiplexer circuits and a driving method that extends the writing time period for gate scanning signals, allowing for increased threshold compensation time, ensuring uniform brightness across OLEDs. This includes a display substrate with multiple gate and data lines arranged in a particular configuration and the use of multiplexer circuits to reduce the number of signal lines and simplify the source driver, along with a driving method that adjusts the writing time periods for gate and data signals to enhance threshold compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution of the display substrate is increased, then the display quality is improved, but the uniformity of brightness across OLEDs deteriorates due to manufacturing tolerances and electrical characteristic drifts
Solution Approach 1:
The patent applies preliminary action by performing threshold voltage compensation before the OLEDs are driven to emit light. The compensation process measures the actual threshold voltages of driving transistors and adjusts the driving currents in advance, thereby compensating for manufacturing tolerances and electrical characteristic drifts before they affect display uniformity. This preliminary compensation action ensures that even with increased resolution, all OLEDs maintain uniform brightness despite variations in transistor characteristics.
2Manufacturing precision
If the writing time period for gate scanning signals is extended to increase threshold compensation time, then the uniformity of brightness is improved, but the refresh rate of the display deteriorates
Solution Approach 1:
The patent applies periodic action by implementing threshold compensation during specific time periods within each frame cycle. The compensation process is performed periodically at predetermined time points (e.g., during horizontal blanking intervals) without extending the overall frame period. This allows sufficient compensation time to be allocated within the existing refresh cycle, maintaining both brightness uniformity and display refresh rate.
Solution Approach 2:
The patent applies dynamics by adaptively adjusting the timing and duration of compensation operations based on the display refresh rate and frame structure. The compensation process dynamically utilizes available time periods (such as horizontal blanking intervals) within each refresh cycle, optimizing the balance between compensation thoroughness and refresh rate without requiring a fixed extension of the writing time period.
3Measurement precision
If multiple data lines are provided for each column of pixel units to enable different data input, then the threshold compensation precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple columns, where each column is independently driven by separate data lines. This allows different data signals to be input to different columns simultaneously, enabling efficient threshold compensation for each column while reducing the overall complexity compared to providing multiple data lines for every pixel. The segmentation strategy balances compensation precision with manageable device complexity.
Solution Approach 2:
The patent applies universality by designing the data line structure to serve multiple functions: during normal operation, data lines drive pixel units to display images, and during compensation periods, the same data lines are used to input compensation data for threshold voltage adjustment. This multi-functionality reduces the need for separate dedicated compensation lines, thereby reducing device complexity while maintaining compensation precision.
Data Source
AI summary
A display substrate includes a display region, a non-display region at a periphery of the display region, pixel units in the display region and arranged in an array, gate lines extending in a row direction of the array, and data lines extending in a column direction of the array. Each row of pixel units is provided with at least one gate line, and each gate line is coupled to at least a part of the pixel units in a corresponding row. Each column of pixel units is provided with at least two data lines, and each data line is coupled to a part of the pixel units in a corresponding column. Each pixel unit is coupled to one gate line and one data line, and two pixel units in a same column and in two adjacent rows are coupled to different data lines, respectively.