OLED Display Power Reduction via Coordinated Voltage Adjustment
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in reducing power consumption while maintaining brightness and color coordinates, as previous methods for dimming operations have limitations in efficiently controlling the voltage levels and gamma values to achieve optimal performance.
Innovation Solution
The proposed solution involves an organic light emitting display device with a pixel unit divided into blocks, each with multiple pixels that compensate for the threshold voltage of driving transistors, and a control system that adjusts the first and second power supply voltages, reference power, and gamma voltages in proportion to the dimming level, allowing for reduced power consumption while maintaining brightness and color coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If dimming operation is performed to limit maximum brightness, then power consumption is reduced, but brightness and color coordinates cannot be maintained
Solution Approach 1:
The patent applies parameter changes by adjusting the first power supply voltage (ELVDD) in proportion to the dimming level while simultaneously adjusting the reference power voltage (Vref) and gamma voltages (Vdata) to compensate for the voltage reduction. This coordinated parameter adjustment maintains the brightness and color coordinates even at reduced power consumption levels. Specifically, when ELVDD is reduced by a certain voltage value, Vref and Vdata are adjusted by corresponding voltage values to ensure the pixel unit maintains its display characteristics.
2Use of energy by moving object
If voltage levels are reduced for power saving, then power consumption decreases, but threshold voltage compensation becomes unstable
Solution Approach 1:
The patent implements feedback through the control system that continuously monitors and adjusts the reference power voltage (Vref) and gamma voltages (Vdata) based on the dimming level. When the first power supply voltage (ELVDD) is reduced, the control system automatically compensates by adjusting Vref and Vdata to maintain stable threshold voltage compensation. This feedback mechanism ensures that the pixel unit's display characteristics remain stable across different dimming levels, preventing degradation of image quality.
3Device complexity
If gamma values are not adjusted with voltage changes, then control complexity is reduced, but color coordinates drift
Solution Approach 1:
The patent applies dynamics by making the gamma voltages (Vdata) and reference power voltage (Vref) adjustable according to the dimming level. Instead of using fixed gamma values, the system dynamically changes these voltages in proportion to the voltage reduction of ELVDD. This dynamic adjustment ensures that color coordinates remain accurate across different brightness levels, from full brightness to dimmed states, maintaining color fidelity throughout the operating range.
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 effectively reduces power consumption by adjusting voltage levels and gamma values, ensuring stable threshold voltage compensation and maintaining image brightness and color coordinates across different dimming levels, thereby enhancing the operational efficiency of the display device.
Implementation Method 1
Each organic light emitting diode emits light based on a recombination of electrons and holes in an active layer
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An organic light emitting display device includes a data driver, a pixel unit, a timing controller, and a power generator. The data driver generates data signals to be supplied to data lines based on gamma voltages. The pixel unit controls the amount of current flowing from a first power supply to a second power supply in each of a plurality of pixels based on the data signals and a reference power voltage. The timing controller limits the maximum brightness of the pixel unit corresponding to a plurality of dimming levels. The first power generator changes the voltage of the first power supply corresponding to the dimming levels.