OLED Display Pixel Deterioration Compensation Using Dummy Pixels
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Solution Overview
Problem
Organic light-emitting diode (OLED) elements experience degradation over time, leading to reduced brightness and requiring increased driving voltage, making it challenging to maintain consistent display performance, and existing compensation techniques struggle to accurately monitor and compensate for this variation.
Innovation Solution
A display device with a deterioration evaluation region and a control circuit that determines the deterioration mode of pixels based on driving history, using dummy pixels to adjust data signals and maintain optimal brightness, employing a light blocking structure to prevent image interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If OLED elements are driven continuously to maintain display functionality, then the display can operate and show images, but the OLED elements deteriorate over time leading to reduced brightness and increased driving voltage requirements
Solution Approach 1:
The patent applies preliminary action by evaluating the deterioration of dummy pixels before they are needed for compensation. The system continuously monitors driving hours and brightness values of dummy pixels, accumulating deterioration data in advance. When a dummy pixel's deterioration reaches a predetermined threshold, it is replaced proactively before it can significantly impact display quality, thus maintaining brightness while extending operational lifetime.
Solution Approach 2:
The patent implements feedback by continuously monitoring the brightness values and driving hours of dummy pixels, comparing them against reference values, and using this information to determine when replacement is needed. The control circuit receives feedback on deterioration status and automatically triggers replacement actions, creating a closed-loop system that maintains optimal brightness while managing OLED lifetime.
2Measurement precision
If the number of dummy pixels in the deterioration evaluation region is increased to improve deterioration monitoring accuracy, then measurement precision improves, but the area occupied by evaluation regions increases
Solution Approach 1:
The patent applies local quality by strategically positioning dummy pixels within the deterioration evaluation region rather than uniformly distributing them. The dummy pixels are placed in locations that provide representative samples of OLED deterioration while minimizing the total area required. This localized approach maintains measurement precision by capturing key deterioration patterns without occupying excessive display area.
Solution Approach 2:
The patent uses copying by creating a simplified model of the display region using dummy pixels that replicate the electrical and optical characteristics of actual display pixels. These dummy pixels serve as copies that undergo the same deterioration processes but are dedicated solely to evaluation purposes, allowing accurate monitoring without requiring a large number of pixels throughout the entire display area.
3Area of stationary object
If the deterioration evaluation region is positioned closer to the display region to reduce area usage, then space efficiency improves, but light from the evaluation region may interfere with the displayed images
Solution Approach 1:
The patent applies the taking out principle by extracting the evaluation function from the display region itself and placing it in a separate deterioration evaluation region. Dummy pixels are positioned in peripheral areas or regions that do not overlap with the active display area, allowing deterioration monitoring to occur independently without causing light interference to the displayed images. This separation maintains both space efficiency and image quality.
Solution Approach 2:
The patent uses an intermediary approach by introducing a dedicated deterioration evaluation region that acts as a mediator between the display region and the monitoring system. This intermediate zone contains dummy pixels that undergo deterioration evaluation without directly interfering with the display output. The evaluation region serves as a buffer that enables monitoring functionality while preventing harmful light interference to the actual display content.
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 identifies and compensates for OLED degradation, ensuring consistent brightness and extending the lifespan of OLED elements by accurately determining deterioration modes and adjusting data signals, while preventing image interference from evaluation regions.
Implementation Method 1
Each of the plurality of display pixels and the plurality of dummy pixels includes a light-emitting element... An organic light-emitting diode (OLED) element is a current-driven light-emitting element
Implementation Method 2
a light blocking part disposed on a side to be viewed of the deterioration evaluation region
Data Source
AI summary
A display device includes a deterioration evaluation region including dummy pixels and a display region. A control circuit determines a gray level for a first display pixel and determines whether the first display pixel is in a first deterioration mode or a second deterioration mode based on a driving history of the first display pixel. The control circuit determines, in the first deterioration mode, a data signal to be supplied to the first display pixel based on the gray level and the driving history of the first display pixel. The control circuit determines, in the second deterioration mode, a data signal to be supplied to the first display pixel based on the gray level, the driving history of the first display pixel, and measurement results about a current-voltage characteristic acquired from dummy pixels in the deterioration evaluation region of the same color as the first display pixel.