OLED Pixel Circuit Transistor Count Compensation for Luminance Uniformity
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Solution Overview
Problem
Conventional organic light emitting displays experience luminance variations due to leakage currents, leading to non-uniform image display because the emission efficiencies of red, green, and blue pixels differ, causing unequal luminance changes despite identical voltage variations in the storage capacitor.
Innovation Solution
The organic light emitting display incorporates red, green, and blue pixels with switch sections and driving circuits, where the number of transistors in each pixel is adjusted based on emission efficiency to minimize leakage current and maintain uniform luminance, with more transistors in high-efficiency pixels and fewer in low-efficiency pixels to compensate for emission efficiency differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of transistors in each pixel is made identical, then the device complexity is reduced and manufacturing is simplified, but luminance uniformity deteriorates due to different emission efficiencies of red, green, and blue pixels causing unequal luminance changes from identical leakage currents
Solution Approach 1:
The patent applies local quality by configuring different numbers of transistors in different pixel types (red, green, blue) based on their specific emission efficiencies. High-efficiency pixels (green) are assigned fewer transistors while low-efficiency pixels (blue) are assigned more transistors, creating localized structural differences that compensate for material property variations and achieve uniform luminance output across all pixels
Solution Approach 2:
The patent changes the parameter of transistor count according to pixel emission efficiency characteristics. By adjusting the number of transistors as a configurable parameter based on measured emission efficiencies of different OLED materials, the system optimizes the balance between leakage current and luminance output to achieve uniform display performance
2Stability of the object's composition
If more transistors are added to low-efficiency pixels to compensate for emission differences, then luminance uniformity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements local quality by tailoring the transistor configuration specifically to each pixel type's emission efficiency characteristics. Rather than uniformly increasing transistor counts across all pixels, the invention selectively adds transistors only where needed (in low-efficiency blue and red pixels) while keeping high-efficiency green pixels simpler, thereby achieving luminance uniformity with minimal overall complexity increase
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 ensures that the luminance variations of red, green, and blue organic light emitting diodes are uniformly set, resulting in a stable and uniform image display regardless of leakage currents.
Implementation Method 1
the organic light emitting displays make use of organic light emitting diodes that emit light by re-combination of electrons and holes
Data Source
AI summary
An organic light emitting display is disclosed capable of displaying an image of uniform luminance regardless of a leakage current. The display includes scan and data lines crossing each other. The display further includes red, green, and blue pixels having red, green, and blue organic light emitting diodes (OLEDs), respectively. Switch sections are respectively included in the red, green, and blue pixels for transferring a data signal to the data lines according to a scan signal from the scan lines. Driving circuits are respectively included in the red, green, and blue pixels for supplying a current to red, green, and blue OLEDs connected thereto according to the data signal from the switch sections. At least one of the respective switch sections included in the red, green, and blue pixels has a different number of transistors than at least one other of the respective switch sections.