Video Signal Correction for OLED Displays Using Inverse EL and TFT Characteristics
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Solution Overview
Problem
Existing organic electroluminescent display devices face challenges in accurately correcting video signals due to non-linear luminance-current and voltage-current characteristics of luminescent elements and drive transistors, leading to suboptimal image quality and potential gradation banding in displays.
Innovation Solution
A display device with a panel characteristics correction unit that includes an EL characteristics correction unit for inverse luminescent characteristics and a TFT characteristics correction unit for inverse drive characteristics, employing multipoint linear and curvilinear approximation methods to independently correct signal corrections for each pixel, ensuring symmetric conversion orders and minimizing circuit size and processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If video signal correction is performed using conventional methods, then correction processing can be implemented, but image quality deteriorates due to non-linear characteristics causing gradation banding and display errors
Solution Approach 1:
The correction processing is divided into two independent correction units: an EL characteristics correction unit that corrects luminance-current non-linearity, and a TFT characteristics correction unit that corrects voltage-current non-linearity. Each unit independently processes specific non-linear characteristics, preventing interaction errors and achieving more accurate overall correction than conventional single-stage methods.
Solution Approach 2:
The correction units apply inverse characteristics to compensate for non-linearities. The EL characteristics correction unit applies inverse luminance-current characteristics, and the TFT characteristics correction unit applies inverse voltage-current characteristics, effectively linearizing the overall system response and eliminating gradation banding.
2Measurement precision
If independent EL and TFT correction units are implemented, then correction accuracy is improved, but device complexity increases
Solution Approach 1:
By segmenting the correction function into two independent units with distinct responsibilities, each unit can be optimized and implemented with minimal circuitry. The EL correction unit handles only luminance-current non-linearity while the TFT correction unit handles only voltage-current non-linearity, reducing the complexity of each individual unit compared to a monolithic correction system.
Solution Approach 2:
The correction units are designed to process multiple correction functions through a unified approach. Each correction unit can handle different types of non-linear characteristics using the same basic correction mechanism, reducing the need for separate dedicated circuits for each correction type.
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 corrects non-linear characteristics, improving image quality by reducing errors in gradation displays and maintaining efficient processing, while allowing for flexible adjustment of correction accuracy and circuit complexity.
Implementation Method 1
an organic electroluminescent element, which is a luminescent element
Implementation Method 2
a pixel circuit configured to supply a drive current to the organic electroluminescent element
Data Source
AI summary
According to one embodiment, a display device includes a plurality of pixels arranged in a matrix on a substrate, each including a luminescent element and a drive transistor configured to supply current to the luminescent element for light emission, and a panel characteristics correction unit configured to correct for display a video signal supplied from outside, to be supplied to a respective one of the pixels, and the panel characteristics correction unit includes an EL characteristics correction unit configured to correct the video signal with inverse luminescent characteristics of the luminescent element, and a TFT characteristics correction unit configured to correct the video signal with inverse drive characteristics of the drive transistor.