OLED Pixel Circuit Reducing Power Consumption via Localized Driving
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Solution Overview
Problem
Conventional organic light emitting displays face high power consumption due to increased driving frequency needed to maintain uniform brightness, particularly in portable devices with separate main and auxiliary regions for image and icon display.
Innovation Solution
The proposed solution involves a pixel structure with specific transistor configurations and a data driver strategy that includes an organic light emitting diode (OLED), transistors, and a storage capacitor to control current flow, minimizing leakage paths and reducing driving frequency, along with a data driver that supplies initializing and data signals in optimized periods to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the driving frequency is increased to maintain uniform brightness in auxiliary regions, then the brightness uniformity is improved, but the power consumption increases
Solution Approach 1:
The patent applies different driving strategies to different regions of the display. The auxiliary region (displaying icons) uses a reduced driving frequency compared to the main region (displaying images), allowing power consumption to be minimized in the auxiliary region while maintaining acceptable brightness uniformity through local adaptation rather than uniform high-frequency driving across the entire display.
Solution Approach 2:
The patent implements periodic initialization of the storage capacitor in the auxiliary region at reduced driving frequency. By periodically charging the storage capacitor with initialization signals at lower frequency intervals, the display maintains uniform brightness in the auxiliary region without requiring continuous high-frequency updates, thereby reducing overall power consumption.
2Use of energy by moving object
If the driving frequency is reduced to minimize power consumption, then the power consumption is improved, but the brightness uniformity deteriorates
Solution Approach 1:
The patent applies preliminary initialization actions by charging the storage capacitor in the auxiliary region with initialization signals before normal operation. This preliminary charging ensures that the storage capacitor maintains sufficient voltage to drive the OLED at reduced frequency without compromising brightness uniformity, allowing the display to operate at lower power consumption levels while maintaining display quality.
Solution Approach 2:
The patent changes the driving parameters specifically for the auxiliary region by applying initialization signals at optimized voltage levels and timing. By adjusting the initialization voltage and timing parameters, the display achieves uniform brightness in the auxiliary region at reduced driving frequency, thereby minimizing power consumption while maintaining acceptable display quality.
3Use of energy by moving object
If additional transistors are added to control current flow and minimize leakage paths, then the power consumption is improved, but the device complexity increases
Solution Approach 1:
The patent segments the pixel circuit into distinct functional regions with dedicated transistors for specific functions: initialization transistor for charging the storage capacitor, driving transistor for controlling OLED current, and emission control transistor for managing emission timing. This segmentation allows each transistor to be optimized for its specific function, minimizing leakage paths without requiring a completely complex redesign of the entire circuit.
Solution Approach 2:
The patent implements dynamic control of transistor states based on operating conditions. The emission control transistor dynamically switches between conducting and non-conducting states based on emission timing signals, and the initialization transistor activates only during initialization periods. This dynamic operation reduces unnecessary current leakage through transistors while maintaining simple circuit architecture, balancing power consumption reduction with device complexity.
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 stabilizes the voltage in the storage capacitor, allowing for reduced driving frequency and minimized power consumption, while maintaining uniform brightness and efficient operation in both main and auxiliary regions of the display.
Implementation Method 1
The organic light emitting display display images using organic light emitting diodes (OLED) that generate light by re-combination of electrons and holes
Data Source
AI summary
A pixel capable of minimizing power consumption is disclosed. In one embodiment, the pixel includes an organic light emitting diode (OLED), a first transistor for controlling an amount of current supplied from a first power supply to the OLED to correspond to a voltage applied to a first node, and a second transistor and a third transistor coupled between a second node electrically coupled to a data line and the first node in parallel in a period where a scan signal is supplied.