Organic EL Display Luminance Compensation via Feedback Sensor
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Solution Overview
Problem
Organic EL display devices experience luminance reduction over time, leading to luminance nonuniformity and 'burn-in' issues due to cumulative light emitting time, which affects image quality.
Innovation Solution
A display device with a screen unit, drive unit, and signal processing unit that includes a light sensor to detect luminance and correct video signals, adjusting the light emitting period of pixel circuits to compensate for luminance deterioration and prevent 'burn-in'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If organic EL elements are used for pixels in a display device, then visibility is higher and response speed is higher compared to liquid crystal display, but luminance reduction occurs with time leading to luminance nonuniformity and burn-in issues
Solution Approach 1:
The patent implements a feedback mechanism where a light sensor detects the actual luminance output of each pixel, and this detection information is fed back to a signal processing unit that adjusts the drive signal to compensate for luminance reduction. This closed-loop feedback system continuously monitors and corrects luminance nonuniformity and burn-in effects, maintaining display quality over time while preserving the high response speed characteristics of organic EL elements.
2Manufacturing precision
If active matrix type is used to achieve large-sized and high-definition display, then display size and definition are improved, but device complexity increases due to TFT control circuits in each pixel
Solution Approach 1:
The patent employs a universal light sensor that can detect luminance from any pixel in the display, and a signal processing unit that handles correction for all pixels through software algorithms. This multi-functional approach replaces the need for dedicated correction circuits in each pixel, reducing device complexity while maintaining high display definition and enabling large-sized displays.
3Reliability
If light sensor is added to detect luminance for compensation, then luminance uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a light sensor as an intermediary component that mediates between the display pixels and the control system. Instead of modifying each pixel circuit individually, the light sensor provides luminance information to a signal processing unit that then adjusts drive signals, simplifying the overall system architecture while achieving luminance uniformity compensation.
Solution Approach 2:
The patent replaces complex hardware-based correction circuits with a software-based signal processing approach. The signal processing unit uses algorithms to calculate compensation values based on light sensor data, substituting mechanical/electrical correction mechanisms with computational methods, thereby reducing device complexity while maintaining compensation effectiveness.
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 luminance reduction and prevents 'burn-in' by correcting video signals based on real-time luminance data, ensuring uniformity and maintaining image quality.
Implementation Method 1
a light sensor arranged in the screen unit. The light sensor outputs a luminance signal in accordance with the light emission
Data Source
AI summary
A display device includes: a screen unit; a drive unit; and a signal processing unit, wherein the screen unit includes rows of scanning lines, columns of signal lines, matrix-state pixel circuits and a light sensor, the drive unit includes a scanner supplying a control signal to the scanning lines and a driver supplying a video signal to the signal lines, the pixel circuit emits light in accordance with the video signal, the light sensor outputs a luminance signal in accordance with the light emission, and the signal processing unit corrects the video signal in accordance with the luminance signal and supplies the signal to the driver.