OLED Hybrid Driving Method Reduces Power Consumption
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Solution Overview
Problem
Conventional OLED display apparatuses face issues with high power consumption and reduced lifespan due to excessive power dissipation and heat generation in driving transistors, caused by fixed high potential voltage application across all pixels in a single frame driving manner.
Innovation Solution
The OLED display apparatus implements a hybrid driving method by varying the high and low potential voltages across subfields and controlling data voltage in an analog manner within each subfield, allowing for dynamic adjustment of drain-source voltage to minimize power loss and optimize grayscale display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed high potential voltage VDD is provided to the driving transistor DT to maintain drain-source voltage Vds at or above the saturation point for all drain-source currents, then the driving transistor can operate in the saturation region for all current levels, but power consumption increases excessively and heat is generated
Solution Approach 1:
The patent applies dynamics by making the high potential voltage VDD adjustable rather than fixed. The voltage is dynamically changed based on the grayscale level (drain-source current) being displayed. For higher grayscale levels requiring higher drain-source currents, a higher VDD is applied; for lower grayscale levels, a lower VDD is applied. This dynamic adjustment allows the driving transistor to maintain saturation region operation across all current levels while minimizing unnecessary power consumption when lower currents are required.
Solution Approach 2:
The patent changes the voltage parameter VDD based on the operating conditions. Specifically, different high potential voltage levels are selected corresponding to different grayscale areas or drain-source current ranges. This parameter change ensures that the drain-source voltage remains sufficient for saturation operation while avoiding excessive voltage application that would cause unnecessary power dissipation and heat generation.
2Reliability
If a fixed high potential voltage VDD is provided to ensure saturation operation at highest current, then all pixels can operate in saturation region, but power is excessively dissipated and lifespan is reduced
Solution Approach 1:
The patent makes the high potential voltage VDD dynamically adjustable according to the required drain-source current level. Instead of always applying the maximum voltage needed for the highest current, the system applies only the necessary voltage for the current level being used. This reduces power dissipation (P=V×I) and heat generation, thereby extending the driving transistor's operational lifespan while maintaining reliable saturation region operation.
Solution Approach 2:
The patent converts the potential harm of excessive power dissipation and heat generation into benefit by implementing intelligent voltage control. By monitoring or determining the required drain-source current level and adjusting VDD accordingly, the system prevents unnecessary power waste and heat accumulation, transforming what would be a harmful condition into a beneficial power management strategy that extends component life.
3Device complexity
If high potential voltage VDD is fixed at one level, then voltage control is simple, but power consumption cannot be optimized for different grayscale levels
Solution Approach 1:
The patent implements dynamic voltage control where the high potential voltage VDD is adjusted based on the grayscale level or drain-source current requirement. The system divides grayscale levels into different areas or ranges, and assigns different VDD levels to each area. This adds some control complexity but achieves significant power consumption optimization by avoiding unnecessary high voltage application during low grayscale display periods.
Solution Approach 2:
The patent changes the voltage parameter VDD according to the operating conditions (grayscale level). By establishing a correspondence between grayscale areas and voltage levels, the system optimizes power consumption efficiency. The increased parameter control complexity is justified by the substantial energy savings achieved through conditional voltage adjustment.
Data Source
Figure 1(A)~1(B)
Figure 2
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AI summary
The present invention provides an organic light emitting diode (OLED) display apparatus displaying a grayscale of one frame with N number of subfields. The OLED display apparatus includes a display panel where pixels are defined by an intersection of data lines and gate lines, a gate driving unit that provides a scan signal to the gate line, and a data driving unit that controls a data voltage in an analog manner. Here, the data voltage is provided to the data line in at least one subfield.