OLED Driving Circuit Subframe Voltage Control
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Solution Overview
Problem
Existing organic electroluminescence displays face challenges in achieving desired grey levels due to uneven threshold voltages and increased charging time for large screens, particularly in active matrix-type displays, which affect image quality and complexity in driving circuits.
Innovation Solution
The implementation of a data driving voltage system that transmits different voltages for each subframe based on the digital data signal, allowing each subframe to emit light corresponding to the number of bits, using a data driving unit, scan driving unit, and control unit to manage scan signals and data signals across multiple power supply lines and emission control lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a data driving voltage system with different voltages for each subframe is implemented, then grey level display precision is improved, but device complexity increases
Solution Approach 1:
The display frame is divided into multiple subframes, with each subframe carrying a specific bit of the digital data signal. This segmentation allows parallel transmission of multiple data bits, improving display precision while managing complexity through structured organization of driving signals across time segments.
Solution Approach 2:
Different data driving voltages are applied periodically to the data driving unit according to the subframe structure. Each subframe receives a specific voltage level corresponding to its data bit, enabling precise grey level control through rhythmic, periodic voltage modulation synchronized with the display refresh cycle.
2Reliability
If multiple subframes are used for digital data signal transmission, then image quality is improved, but driving circuit complexity increases
Solution Approach 1:
The digital data signal is segmented into multiple bits, with each bit transmitted during a separate subframe. This segmentation enables reliable image quality through bit-parallel transmission while organizing the driving circuit complexity into manageable, repeating subframe cycles with standardized control logic.
Solution Approach 2:
The driving circuit is pre-configured with subframe-specific voltage levels and timing sequences. Before each subframe period, the circuit prepares the appropriate data driving voltage based on the corresponding data bit, enabling smooth transitions and reducing complex real-time control requirements during operation.
3Loss of time
If data driving voltages are changed for each subframe, then charging time is reduced, but power consumption increases
Solution Approach 1:
Data driving voltages are applied in periodic subframe cycles, with each subframe receiving a voltage pulse corresponding to its data bit. This periodic application reduces overall charging time by utilizing idle periods between subframes, while the pulsed nature of the voltage application minimizes continuous power consumption compared to sustained voltage levels.
Solution Approach 2:
Different voltage levels are applied locally to specific data driving units based on their corresponding subframe requirements. Each data line receives only the voltage necessary for its specific subframe, avoiding unnecessary power consumption in other lines and enabling optimized energy distribution across the display matrix.
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 enables the organic electroluminescence display to effectively display desired grey levels by controlling current flow through transistors with varying data driving voltages, minimizing image unevenness and ensuring consistent emission periods for each bit of the digital signal, thus improving image quality and simplifying the driving circuitry.
Implementation Method 1
The organic electroluminescence device (OLED) has an organic film formed between an anode electrode and a cathode electrode so that the organic film is allowed to emit light. Light is emitted from the organic film if a current flows from the anode electrode to the cathode electrode.
Data Source
AI summary
An organic electroluminescence display transmits a data driving voltage to a data driving unit to make different a voltage of the data signal outputted from the data driving unit, the data driving voltage being in a different level in every subframe according to the digital data signal, and displaying a desired grey level of an image by allowing a desired subframe to emit light according to the number of bits of the data signal, and a driving method thereof. An organic electroluminescence display includes a plurality of scan lines to transmit a scan signal; a plurality of data lines to transmit a digital data signal; and a plurality of pixels defined by a plurality of power supply lines to supply power, wherein the scan signal is transmitted to a plurality of subframes, and ON signals of the digital data signal have different voltages in a plurality of the subframes.