OLED Display Power Reduction via Dynamic Voltage and Transistor Mode Switching
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Solution Overview
Problem
Organic light emitting displays used in small portable devices face challenges in reducing power consumption without compromising picture quality, as they are typically driven by limited portable power sources.
Innovation Solution
An organic light emitting display system that includes a scan driver, data driver, timing controller, and power source, allowing for a normal driving mode and a standby driving mode, where the voltage difference between power sources is adjusted to reduce power consumption, and driving transistors are operated as switches in the standby mode to minimize leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage difference between power sources is reduced in standby mode to save energy, then power consumption is reduced, but the ability to maintain display quality may be compromised
Solution Approach 1:
The patent applies dynamics by making the voltage difference between power sources adjustable based on operating mode. In normal mode, a first voltage difference maintains full display quality, while in standby mode, a second voltage difference (different from the first) reduces power consumption. The driving transistors dynamically switch between saturation region operation (normal mode) and linear region operation (standby mode), allowing the system to adapt its electrical characteristics to different operational requirements.
Solution Approach 2:
The patent changes the electrical parameters (voltage difference and transistor operating region) based on the display's operational state. By setting the voltage difference between first and second power sources to a first value in normal mode and a second value in standby mode, the system optimizes power consumption while maintaining acceptable display functionality. The driving transistors' operating region is also changed from saturation to linear region depending on the mode.
2Use of energy by moving object
If driving transistors are operated as switches in standby mode to minimize leakage current, then power consumption is reduced, but the ability to display gray levels is limited
Solution Approach 1:
The patent makes the transistor operating region dynamic, switching between saturation region (for gray level display in normal mode) and linear region (for low-power switching in standby mode). This dynamic operation allows the same transistor circuit to perform different functions optimally depending on the operational mode required.
Solution Approach 2:
The patent changes the operating parameters of the driving transistors by adjusting the voltage difference between power sources and the bias conditions, thereby transitioning the transistors between saturation and linear regions. This parameter change enables the system to achieve low leakage current in standby mode while maintaining the ability to display gray levels when needed.
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
The system effectively reduces power consumption by lowering the voltage difference in standby mode and operating transistors as switches, maintaining emission or non-emission states, allowing the display to be driven with reduced frequency without significant brightness changes.
Implementation Method 1
the organic light emitting display displays images using organic light emitting diodes (OLEDs) that generate light by the re-combination of electrons and holes
Data Source
AI summary
An organic light emitting display is capable of reducing power consumption. The organic light emitting display includes a scan driver for sequentially supplying scan signals to scan lines, a data driver for supplying data signals to data lines in synchronization with the scan signals, pixels located at crossing regions of the scan lines and the data lines, a timing controller for determining a normal driving mode for displaying a normal image and a standby driving mode displaying less information than the normal image, and a power source for supplying a first power and a second power to the pixels, wherein a voltage difference between the first power and the second power in the normal driving mode is a first voltage, and a voltage difference between the first power and the second power is a second voltage different from the first voltage.