OLED Driving Method Synchronizes Turn-On Times
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Solution Overview
Problem
Current OLED display technologies face challenges in achieving consistent turn-on times across different grayscale brightness levels, leading to issues like smearing color cast during image transitions, due to asynchronous lighting caused by parasitic capacitance delays in the backplane.
Innovation Solution
A driving method for OLED display panels that adjusts the duty ratio and data voltage for each light emitting unit based on predetermined brightness bands, ensuring a current greater than a preset reference current and an ON duration less than a preset reference duration, thereby synchronizing turn-on times across different grayscale levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OLED driving methods are used with fixed duty ratio and data voltage, then the display can operate with simple circuit design, but the turn-on times of different light emitting units become inconsistent leading to smearing color cast
Solution Approach 1:
The patent applies dynamics by making the duty ratio and data voltage adjustable rather than fixed. The driving circuit dynamically changes these parameters based on grayscale brightness levels, allowing different light emitting units to synchronize their turn-on times while maintaining circuit simplicity. This resolves the contradiction by enabling adaptability without requiring complex hardware modifications.
Solution Approach 2:
The patent changes operating parameters (duty ratio and data voltage) to resolve the turn-on time inconsistency issue. By adjusting these parameters according to different grayscale brightness levels, the system achieves consistent turn-on times across RGB light emitting units without modifying the physical circuit structure, thus improving reliability while keeping device complexity low.
2Reliability
If the ON duration is increased to allow consistent turn-on across different grayscale levels, then turn-on consistency improves, but the power consumption increases
Solution Approach 1:
The patent changes the duty ratio parameter based on grayscale brightness levels. For higher grayscale levels where longer turn-on time is needed for consistency, the duty ratio is increased. For lower grayscale levels, the duty ratio is decreased to reduce power consumption. This dynamic parameter adjustment resolves the contradiction between turn-on consistency and power consumption.
3Reliability
If different data voltages are applied to different light emitting units to compensate for parasitic capacitance delays, then turn-on time consistency improves, but the circuit design becomes more complex
Solution Approach 1:
The patent applies different data voltage levels to different light emitting units based on their specific parasitic capacitance characteristics. By adjusting the data voltage parameter rather than modifying the circuit structure, the system compensates for timing delays and achieves consistent turn-on times. This approach resolves the contradiction by using parameter adjustment instead of complex circuit redesign.
4Use of energy by moving object
If the duty ratio is decreased to reduce power consumption, then energy efficiency improves, but the ON duration becomes insufficient for consistent turn-on across different grayscale levels
Solution Approach 1:
The patent dynamically adjusts the duty ratio parameter based on grayscale brightness levels. For higher grayscale levels requiring longer turn-on time, the duty ratio is increased to ensure consistent turn-on. For lower grayscale levels where less energy is needed, the duty ratio is decreased to improve power efficiency. This conditional parameter adjustment resolves the contradiction between power consumption and turn-on consistency.
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 significantly reduces smearing color cast and improves display quality by ensuring consistent turn-on speeds of RGB light emitting units, maintaining actual grayscale brightness without hardware changes and at a low implementation cost.
Implementation Method 1
a light emitting device electrically connected to the pixel circuit. The pixel circuit is configured to output a current to the light emitting device to drive the light emitting device to emit light
Data Source
AI summary
A driving method of a display panel includes: determining a brightness band of the display panel, wherein brightness bands include a first brightness band to an Nth brightness band, maximum grayscale brightness of the first brightness band to the Nth brightness band decreases sequentially, and each brightness band includes three Gamma correction curves respectively corresponding to a first light emitting unit, a second light emitting unit, and a third light emitting unit each of an (N−M)th brightness band to the Nth brightness band also corresponds to at least one duty ratio; determining an input data voltage corresponding to at least one light emitting unit based on a Gamma correction curve that corresponds to the determined brightness band and an image to be displayed; and driving the display panel to display the image based on the determined input data voltage, or the determined input data voltage and the duty ratio.