Display Correction Method for Organic EL Threshold Voltage Variation
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Solution Overview
Problem
Display unevenness caused by variations in characteristics of organic EL elements in pixels, and deterioration of these elements due to moisture, oxygen, light, and heat, leading to decreased luminance and color accuracy over time.
Innovation Solution
A correction method for a display apparatus that includes a pixel with a light-emitting element, a transistor, and a capacitor. The method involves processing steps to correct the threshold voltage of the transistor, measure current flowing through the pixel, generate signals based on the current measurements, and adjust image data to ensure consistent display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If organic EL elements are used in display apparatus, then high response speed and thin structure are achieved, but display unevenness occurs due to variations in characteristics of organic EL elements
Solution Approach 1:
The patent implements a feedback mechanism where the current flowing through the light-emitting element is measured, and this measurement is used to generate a correction signal. The correction signal adjusts the drive signal to compensate for variations in organic EL element characteristics, thereby maintaining display uniformity while preserving the high response speed advantage
Solution Approach 2:
The patent changes the drive method by introducing a correction signal that dynamically adjusts the drive voltage or current based on measured element characteristics. This parameter adjustment compensates for variations between elements, achieving uniform display without sacrificing the inherent fast response of organic EL materials
2Illumination intensity
If organic EL elements are driven at high luminance, then bright display is achieved, but deterioration of elements is accelerated by moisture, oxygen, light, and heat
Solution Approach 1:
The patent uses feedback control where the actual current through the light-emitting element is measured and used to generate a correction signal. This enables precise control of drive conditions to achieve required luminance while minimizing excessive stress on the elements, thereby extending durability
Solution Approach 2:
The patent performs preliminary characterization of each light-emitting element's characteristics before normal operation. By measuring initial current-voltage characteristics and generating correction signals in advance, the system can operate elements within safe parameters from the start, preventing accelerated deterioration while maintaining high luminance capability
3Adaptability or versatility
If different colors of organic EL elements are used for color display, then full-color display is achieved, but elements deteriorate at different speeds causing luminance differences over time
Solution Approach 1:
The patent implements separate feedback control for each color element (R, G, B), measuring the current through each light-emitting element independently and generating individual correction signals. This enables independent optimization and compensation for each color channel, maintaining luminance consistency across different colors over time while preserving full-color display capability
Solution Approach 2:
The patent applies local quality control by treating each color element (R, G, B) with individual correction based on its specific characteristics. Each element receives customized drive signals and correction amounts tailored to its particular deterioration rate and electrical characteristics, ensuring uniform aging behavior across different colors
4Manufacturing precision
If correction processing is added to compensate for element variations, then display quality is improved, but device complexity increases
Solution Approach 1:
The patent uses a universal correction approach where a single correction signal generation circuit serves all light-emitting elements regardless of color or position. The correction mechanism is integrated into the existing drive circuitry, with the same basic structure used for R, G, and B elements, thereby improving display quality without proportionally increasing device complexity
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 method achieves high display quality by correcting for variations in transistor threshold voltage and light-emitting element characteristics, thereby reducing display unevenness and maintaining consistent luminance across different color elements.
Implementation Method 1
a voltage correcting a threshold voltage of the transistor is obtained and the voltage is held in the capacitor
Implementation Method 2
By voltage application to this element, light emission can be obtained from the light-emitting organic compound
Data Source
AI summary
A novel correction method of a display apparatus is provided. One embodiment of the present invention is a correction method of a display apparatus. The correction method includes processing in which a voltage correcting a threshold voltage of the transistor is obtained and the voltage is held in the capacitor; processing in which current flowing through the pixel is measured and a second signal based on the current is generated in the first circuit; processing in which the first signal correcting image data using the second signal is generated in the second circuit; and processing in which the first signal is supplied to the pixel.