Pixel Circuit Compensation for OLED Luminance Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting devices suffer from luminance deviation between pixels due to varying threshold voltage and non-uniform semiconductor characteristics, leading to blurred motion and uneven image display.
Innovation Solution
A display device with a pixel structure that includes a light-emitting element, driving transistor, capacitor, switching transistor, emission control transistor, compensation transistors, and reset transistor, which applies compensation voltages to adjust threshold voltage and mobility, ensuring uniform luminance by varying the intensity of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pixel structure with basic driving transistor and capacitor is used, then the device complexity is low, but luminance uniformity deteriorates due to threshold voltage variation and mobility deviation
Solution Approach 1:
The patent applies preliminary compensation actions by introducing compensation transistors that pre-adjust for threshold voltage variations and mobility deviations before the main driving operation. The first compensation transistor compensates threshold voltage in advance, while the second compensation transistor compensates mobility variations, ensuring uniform luminance output across all pixels before the actual display operation begins.
Solution Approach 2:
The patent changes key electrical parameters by introducing compensation mechanisms that actively adjust threshold voltage and mobility parameters. The compensation transistors modify the effective threshold voltage and mobility values through controlled current paths, transforming the fixed parameter approach into a dynamically adjustable parameter system that adapts to manufacturing variations.
2Manufacturing precision
If multiple compensation transistors and control circuits are added to compensate threshold voltage and mobility, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing compensation transistors that simultaneously address multiple issues. The first compensation transistor handles threshold voltage compensation while the second handles mobility compensation, and both work within the same pixel structure framework. This universal approach allows a single compensation mechanism to address multiple sources of luminance non-uniformity without requiring separate independent systems for each compensation type.
3Manufacturing precision
If threshold voltage compensation is applied, then luminance uniformity is improved, but the device requires additional compensation transistors and control signals
Solution Approach 1:
The patent introduces compensation transistors as intermediary elements that mediate between the data voltage input and the light-emitting element. These intermediary transistors provide a controlled path for compensation currents, acting as mediators that adjust the electrical characteristics without directly modifying the core driving structure. The intermediary compensation transistors enable threshold voltage compensation while maintaining the fundamental pixel architecture.
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 solution effectively compensates for threshold voltage and mobility deviations, resulting in uniform luminance across pixels, reducing blurriness and improving motion clarity in displayed images.
Implementation Method 1
a capacitor connected between the second node and a driving voltage terminal
Implementation Method 2
a light-emitting element... emitting light at the light-emitting element
Data Source
AI summary
A display device and a driving method thereof. The display device includes a plurality of pixels arranged in a matrix. Each pixel includes a light-emitting element, a driving transistor including an input terminal connected to a first node, a control terminal connected to a second node, and an output terminal, a capacitor connected between the second node and a driving voltage terminal, a switching transistor to transmit a data voltage to the first node, an emission control transistor connected between the output terminal of the driving transistor and the light-emitting element, a first compensation transistor connected between the second node and the output terminal of the driving transistor, a second compensation transistor to transmit a mobility compensation voltage to the first node, a driving control transistor to transmit a driving voltage to the first node, and a reset transistor to transmit a reset voltage to the emission control transistor.