Image Display Device Voltage Drop Correction
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Solution Overview
Problem
Conventional active matrix image display devices experience irregularity in brightness levels and image quality due to voltage drops in power source lines, causing variations in gate voltage and current flow across pixel circuits, leading to issues like cross-talk and image deterioration.
Innovation Solution
A method and device that corrects image data based on expected voltage drops in power source lines, adjusting the image signal to maintain consistent brightness levels across pixel circuits by deriving and applying correction values to the image signal line, ensuring consistent current flow and reduced voltage drop effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pixel circuits are connected in common to an IC through one power source line, then device complexity is reduced, but voltage drop causes brightness level irregularity and image quality deterioration
Solution Approach 1:
The patent divides the power source lines into multiple independent lines (first power source line and second power source line) to supply power to different groups of pixel circuits. This segmentation prevents voltage drops in one line from affecting all pixel circuits, thereby maintaining brightness uniformity while keeping the overall device complexity manageable.
Solution Approach 2:
The patent applies different potential values to different regions of pixel circuits by using multiple power source lines with different potentials. Specifically, pixel circuits closer to the IC receive different potentials than those farther away, compensating for voltage drops and ensuring local brightness quality is maintained across the entire display.
2Ease of manufacture
If power source potential is supplied through a common line to reduce wiring complexity, then ease of manufacture is improved, but voltage drop leads to gate voltage variation and current flow inconsistency
Solution Approach 1:
The patent segments the power source supply into multiple independent lines, each serving specific pixel circuits. This segmentation ensures that current flow in one line does not affect other lines, maintaining reliability and current consistency while preserving manufacturing simplicity through a modular approach.
Solution Approach 2:
The patent introduces multiple power source lines as intermediaries between the IC and pixel circuits. These intermediary lines act as separate current paths, preventing current flow in one path from affecting others, thereby ensuring reliable and consistent current delivery to each pixel circuit group.
3Device complexity
If a single power source line is used to supply negative potential, then device structure is simplified, but voltage drop causes brightness level variation and cross talk
Solution Approach 1:
The patent divides the power source line structure into multiple independent lines, each supplying power to specific pixel circuit groups. This segmentation eliminates the cross-talk effect where voltage drops in one region would affect adjacent regions, while maintaining relatively simple device structure through the modular line configuration.
Solution Approach 2:
The patent implements local quality control by assigning different power source potentials to different spatial regions of pixel circuits. This ensures that each local region receives the appropriate potential to maintain uniform brightness, preventing the brightness irregularities and cross-talk that would occur with a single common power line.
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 improves image quality by maintaining consistent brightness levels and reducing irregularities, thereby enhancing the overall display performance and reducing image deterioration caused by voltage drop variations.
Implementation Method 1
a potential applied from the power source line to each pixel circuit may change based on the wiring resistance and a flowing current
Implementation Method 2
The power source line has wiring resistance
Implementation Method 3
a current control light emitting element such as an OLED (organic light emitting diode)
Data Source
AI summary
Discussed is a method of driving an image display device including a plurality of pixel circuits having respective light emitting elements and arranged in a plane in a first direction and in a second direction different from the first direction; and a plurality of power source lines each connected in common to each column of pixel circuits which comprises the pixel circuits arranged in the first direction comprises (a) deriving a voltage drop expected to be generated in one power source line based on the wiring resistance of the one power source line and first image data supplied to a plurality of pixel circuits connected in common to the one power source line; (b) deriving second image data by correcting the first image data based on the voltage drop; and (c) causing the light emitting elements to emit light based on the second image data.