OLED Subpixel Voltage Segmentation for Power Efficiency
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Solution Overview
Problem
Active matrix OLED displays face inefficiencies in power consumption due to excess voltage drop across power transistors when subpixels operate at lower intensity, leading to reduced power efficiency and uneven subpixel lifetimes.
Innovation Solution
The method involves selecting subpixels of different colors with operating voltages based on maximum current density requirements, ensuring the display operating voltage is equal to or greater than the maximum required subpixel voltage, and adjusting subpixel areas to reduce the maximum operating voltage, thereby reducing power consumption and improving color balance over the device's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the voltage is set to drive the most demanding subpixels at maximum luminance, then all subpixels can operate at full brightness, but power consumption increases and power efficiency decreases
Solution Approach 1:
The patent implements dynamic voltage adjustment by dividing subpixels into groups with different maximum luminance capabilities. The display operates at different voltage levels depending on which subpixel group is being driven, allowing the system to adapt its power consumption to the actual display requirements rather than always operating at maximum voltage
Solution Approach 2:
The patent changes the voltage parameter dynamically based on the subpixel group being driven. By setting different maximum operating voltages for different subpixel groups (first group at higher voltage, second group at lower voltage), the system optimizes power consumption while maintaining the ability to display full-color images
2Illumination intensity
If the voltage is set to drive the most demanding subpixels, then full brightness is achieved, but the voltage drop across power transistors increases reducing power efficiency
Solution Approach 1:
The patent dynamically adjusts the operating voltage based on which subpixel group is active. When driving subpixels from the second group, the system uses a lower voltage level, thereby reducing the voltage drop across power transistors and improving power efficiency while still achieving adequate brightness for that subpixel group
3Device complexity
If different colored subpixels are connected to the same power line, then circuit complexity is reduced, but subpixels with different maximum voltage levels experience poor power efficiency
Solution Approach 1:
The patent segments the subpixels into different groups based on their voltage requirements and connects each group to dedicated power lines. This segmentation allows each power line to be optimized for its specific voltage level, improving power efficiency while maintaining manageable circuit complexity through systematic organization
Solution Approach 2:
The patent applies local quality by providing different voltage levels to different subpixel groups through separate power lines. Each power line is tailored to the specific voltage requirements of its associated subpixels, allowing optimal power efficiency for each local group rather than using a single voltage level for all subpixels
4Use of energy by moving object
If subpixels operate at lower intensity, then power consumption is reduced, but the voltage drop across power transistors increases further reducing power efficiency
Solution Approach 1:
The patent implements dynamic voltage scaling where the system switches to a lower voltage operating mode when driving subpixels from the second group at lower intensity. This dynamic adjustment ensures that the voltage drop across power transistors remains minimized even when operating at reduced brightness levels, maintaining power efficiency across different intensity ranges
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 enhances power efficiency, lowers overall power consumption, and extends the device's lifetime while maintaining color balance by optimizing subpixel voltages and areas to match their respective current density demands.
Implementation Method 1
The organic electroluminescent media supports recombination of holes and electrons to cause light emission
Data Source
AI summary
A method for making an OLED device, including: providing a plurality of subpixels of different colors, including at least three gamut-defining subpixels, each subpixel requiring an operating voltage which is based on the maximum current density required by that subpixel; selecting the display operating voltage to be equal to or greater than the maximum required subpixel operating voltage; and selecting the area of the subpixels to reduce the maximum required subpixel operating voltage, thereby reducing the display operating voltage so as to reduce power consumption in the device.