Display Pixel Demultiplexing to Reduce Amplifiers and Preserve Writing Time
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Solution Overview
Problem
As display panel resolution increases, the number of amplifiers in data drivers increases, leading to higher manufacturing costs and insufficient data writing time for pixels.
Innovation Solution
A display device employing a demultiplexer driving method where one amplifier is connected to multiple data lines, with data voltages written in separate periods using a demultiplexer and transistors to ensure sufficient data writing time while reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of amplifiers in the data driver is increased to support higher display panel resolution, then the signal strength and data transmission capability are improved, but the manufacturing cost increases and the data writing time becomes insufficient
Solution Approach 1:
The patent applies the demultiplexer driving method where one amplifier is shared across multiple data lines through time-division multiplexing. The amplifier sequentially connects to different data lines (e.g., DATA1, DATA2, DATA3, DATA4) in successive time periods, allowing a single amplifier to serve multiple functions that would traditionally require multiple dedicated amplifiers, thus reducing device complexity while maintaining data transmission capability
Solution Approach 2:
The patent implements periodic time-division multiplexing where the amplifier switches between different data lines in sequential time periods. Each data line is assigned a specific time slot (e.g., first period, second period, third period, fourth period) within a frame period, creating a periodic action pattern that allows one amplifier to service multiple data lines without simultaneous conflicts, thereby reducing the total number of amplifiers needed
2Device complexity
If the number of amplifiers is reduced using demultiplexer driving method, then the manufacturing cost is reduced, but the data writing time for pixels becomes insufficient
Solution Approach 1:
The patent segments the data writing process into distinct time periods within a frame period. Each data line is assigned a specific time slot for data voltage transmission (e.g., first period for DATA1, second period for DATA2), and the compensation period is separated from the writing period. This temporal segmentation allows sufficient time allocation for data writing while using fewer amplifiers through multiplexing
Solution Approach 2:
The patent performs compensation action in advance during a separate compensation period before the actual data writing period. The compensation gate signal is applied to compensate for threshold voltage shifts of switching transistors before data is written to the pixel. This preliminary compensation action ensures that when data writing occurs in the subsequent writing period, the transistors are already optimized for accurate data storage, allowing faster and more efficient data writing
3Speed
If time for transmitting data voltage to data line is reduced, then the transmission speed is improved, but the data writing time for pixels is insufficient
Solution Approach 1:
The patent performs preliminary data voltage transmission to data lines during dedicated time slots before the pixel writing period. The demultiplexer transmits data voltages to multiple data lines in sequence during the frame period, and the compensation period is separated from the writing period. This preliminary action allows data to be prepared and transmitted efficiently without compromising the subsequent data writing time to pixels
Solution Approach 2:
The patent segments the data transmission process into distinct time periods where data voltages are transmitted to different data lines sequentially. Each data line receives its data voltage during a specific time slot (first period, second period, etc.), and this segmented approach ensures that transmission time is optimized while maintaining sufficient time for pixel writing operations
Data Source
AI summary
A display device includes first and second pixels disposed in a pixel row, first and second data lines connected to the first and second pixels, respectively, a data driver providing first and second data voltages to a first output line, and a demultiplexer selectively connecting the first and second data lines to the first output line. Each of the first and second pixels includes a first transistor, a second transistor, a third transistor, a first capacitor, and a light emitting element. The first data voltage is written to the first pixel through the first data line in a first period of a writing period in which a write gate signal has a turn-on voltage level, and the second data voltage is written to the second pixel through the second data line in a second period of the writing period that is after the first period.