OLED Luminance Uniformity via Auxiliary Transistors
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Solution Overview
Problem
Organic light-emitting display devices face issues with luminance unevenness, which affects image quality due to variations in the driving current and voltage distribution across pixels.
Innovation Solution
The introduction of auxiliary and reference transistors on each horizontal line, coupled with a power source and a reference power source respectively, allows for controlled driving current and voltage management, ensuring uniform luminance by discharging the organic capacitor and optimizing the black expression performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pixel circuits are used without auxiliary and reference transistors, then the device complexity is low, but luminance unevenness occurs affecting image quality
Solution Approach 1:
The patent introduces auxiliary transistors and reference transistors as intermediary components between the pixel circuit and power sources. These transistors act as mediators to regulate and equalize the voltage and current distribution across pixels, thereby eliminating luminance unevenness without requiring fundamental changes to the pixel structure.
Solution Approach 2:
The patent modifies the electrical parameters (voltage and current) supplied to each pixel by introducing controllable transistor switches. By dynamically adjusting the driving current through the auxiliary and reference transistors, the system compensates for variations in pixel characteristics and achieves uniform luminance output across the display.
2Manufacturing precision
If auxiliary and reference transistors are added to each pixel, then luminance uniformity is improved, but the number of transistors per pixel increases
Solution Approach 1:
The patent divides the display into horizontal lines, with each line having its own auxiliary transistor and reference transistor. This segmentation allows for line-by-line compensation of luminance variations, reducing the need for more transistors per pixel while still achieving overall luminance uniformity across the entire display.
Solution Approach 2:
The auxiliary transistors and reference transistors serve multiple functions: they act as switches for voltage storage, current regulation elements, and compensation mechanisms for luminance unevenness. By making these transistors multi-functional, the patent reduces the total number of transistors needed compared to having separate dedicated components for each function.
3Manufacturing precision
If more transistors are used for voltage storage and current control, then black expression performance is enhanced, but the area occupied by each pixel increases
Solution Approach 1:
The patent merges the voltage storage function and current control function into the same auxiliary transistor structure. By combining these functions that could have been implemented with separate components, the design achieves improved black expression performance while minimizing the additional area required per pixel.
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 solution mitigates luminance unevenness, enhances black expression, and improves overall image quality by ensuring consistent light emission across the display device.
Implementation Method 1
The organic light-emitting display device displays an image using organic light-emitting diodes which generate light by recombination of electrons and holes
Data Source
AI summary
An organic light-emitting display device including: pixels disposed on each of horizontal lines, each of the pixels includes an organic light-emitting diode, and an auxiliary transistor coupled between an anode electrode of the organic light-emitting diode and an auxiliary power source; and at least one reference transistor disposed on each of the horizontal lines and coupled between a reference power source and at least one of the pixels. The auxiliary transistor and the reference transistor may be simultaneously turned on.