Display Panel Demultiplexing Driving to Prevent Data Line Coupling
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Solution Overview
Problem
In display devices employing a demultiplexing driving scheme, securing sufficient threshold voltage compensation time for sub-pixels without causing coupling between data lines is challenging, especially when using a reduced number of source channels to minimize manufacturing costs.
Innovation Solution
A display panel configuration with specific pixel group arrangements and scan timing, where sub-pixels are driven in alternating sequences to prevent data line coupling, utilizing a demultiplexer circuit to selectively couple source channels to data lines, eliminating the need for dummy source channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a demultiplexing driving scheme is employed to reduce the number of source channels, then manufacturing cost is reduced, but sufficient threshold voltage compensation time cannot be secured
Solution Approach 1:
The scan-on time is segmented into multiple scan-off times interspersed throughout the frame period. These scan-off times are distributed segments of the total compensation time, allowing threshold voltage compensation to occur in multiple intervals rather than requiring one continuous block of time. This segmentation enables sufficient total compensation time while maintaining a reduced number of source channels for cost efficiency.
Solution Approach 2:
The scan-off times are positioned at predetermined intervals during the frame period, performing threshold voltage compensation in advance before the next scanning operation. By scheduling these compensation intervals preliminarily throughout the frame period, the system ensures that transistors are ready for the next scan cycle without requiring extended continuous compensation time.
2Loss of time
If two data lines are disposed between adjacent sub-pixel columns to secure compensation time, then sufficient threshold voltage compensation time is secured, but coupling between data lines occurs
Solution Approach 1:
The patent extracts the data line coupling problem by eliminating the physical structure causing it (two data lines between adjacent columns) and replaces it with a temporal solution. Instead of using spatial separation through additional data lines, the system uses time-division multiplexing where data voltages are applied sequentially during different time intervals, preventing coupling while maintaining sufficient compensation time through the segmented scan-off periods.
Solution Approach 2:
The system employs periodic action by alternating between scan-on periods (for data writing) and scan-off periods (for threshold voltage compensation) in a regular cycle throughout the frame period. This periodic switching between operational modes prevents data line coupling during data writing while ensuring regular threshold voltage compensation occurs during the interspersed scan-off times, resolving both contradictions simultaneously.
3Object-affected harmful factors
If a driving method simultaneously driving two data lines is used to prevent coupling, then data line coupling is prevented, but dummy source channels are required
Solution Approach 1:
The existing source channels are made multi-functional by using them for both data writing during scan-on periods and threshold voltage compensation during scan-off periods. Instead of requiring dedicated dummy source channels for compensation, the same source channels perform dual functions at different time intervals, eliminating the need for additional hardware while preventing data line coupling through temporal separation.
Solution Approach 2:
The source channels maintain continuous useful action throughout the frame period by alternating between data writing and threshold voltage compensation tasks. Rather than having idle dummy source channels, the system keeps all source channels actively performing useful functions continuously, switching between operations based on the scan-on/scan-off timing, thereby eliminating the need for dummy channels while maintaining both data integrity and transistor performance.
Data Source
AI summary
A display panel includes a first pixel group including sub-pixels coupled to a first scan line and located in first through N-th sub-pixel columns, where N is an even number greater than or equal to 2, a second pixel group including sub-pixels coupled to the first scan line and located in (N+1)-th through 2N-th sub-pixel columns, a third pixel group including sub-pixels coupled to a second scan line adjacent to the first scan line and located in the first through N-th sub-pixel columns, and a fourth pixel group including sub-pixels coupled to the second scan line and located in the (N+1)-th through 2N-th sub-pixel columns. The first pixel group and the second pixel group are driven during a first scan on time in which the first scan line is driven. Consecutive N−1 sub-pixels among the sub-pixels of the third pixel group and one sub-pixel among the sub-pixels of the fourth pixel group are driven during a first portion of a second scan on time in which the second scan line is driven, and consecutive N−1 sub-pixels among the sub-pixels of the fourth pixel group and one sub-pixel among the sub-pixels of the third pixel group are driven during a second portion of the second scan on time.