OLED Driving Transistor Range Configuration for Color Accuracy
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Solution Overview
Problem
Organic light emitting diode displays experience color variation issues at low gray levels due to differences in the current-luminance ratio among red, green, and blue pixels, leading to inconsistent luminance and color accuracy.
Innovation Solution
The display incorporates a unique configuration where the driving range of each pixel's driving transistor is tailored to match the current-luminance ratio, with the green pixel having the largest driving range, the red pixel intermediate, and the blue pixel the smallest, achieved through varying the width, length, and doping of the driving channel, as well as the thickness of the gate insulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all driving transistors have the same current magnitude in response to the same applied voltage, then the driving range is consistent across pixels, but color variation occurs at low gray levels due to different current-luminance ratios in red, green, and blue pixels
Solution Approach 1:
The patent applies local quality by configuring driving transistors with different driving ranges according to the specific characteristics of each pixel type. Red, green, and blue pixels are assigned different driving range values (e.g., red: 1.0-1.5V, green: 0.8-1.2V, blue: 0.6-1.0V) matched to their respective current-luminance ratios, allowing each pixel to operate optimally within its own parameter range rather than using a uniform configuration across all pixels.
Solution Approach 2:
The patent implements parameter changes by adjusting the driving range parameter of driving transistors based on the current-luminance ratio characteristics of different pixel types. The driving range is modified as a key parameter to compensate for the inherent differences in luminance efficiency among red, green, and blue pixels, thereby achieving consistent color accuracy across the display.
2Reliability
If the driving range is increased for pixels with higher current-luminance ratio, then color variation at low gray levels is reduced, but the device complexity increases due to different transistor configurations
Solution Approach 1:
The patent applies local quality by configuring driving transistors with different driving ranges according to the specific characteristics of each pixel type. Red, green, and blue pixels are assigned different driving range values (e.g., red: 1.0-1.5V, green: 0.8-1.2V, blue: 0.6-1.0V) matched to their respective current-luminance ratios, allowing each pixel to operate optimally within its own parameter range rather than using a uniform configuration across all pixels.
Solution Approach 2:
The patent implements parameter changes by adjusting the driving range parameter of driving transistors based on the current-luminance ratio characteristics of different pixel types. The driving range is modified as a key parameter to compensate for the inherent differences in luminance efficiency among red, green, and blue pixels, thereby achieving consistent color accuracy across the display.
3Reliability
If the driving range is tailored to match current-luminance ratio, then luminance sensitivity to current variation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by configuring driving transistors with different driving ranges according to the specific characteristics of each pixel type. Red, green, and blue pixels are assigned different driving range values (e.g., red: 1.0-1.5V, green: 0.8-1.2V, blue: 0.6-1.0V) matched to their respective current-luminance ratios, allowing each pixel to operate optimally within its own parameter range rather than using a uniform configuration across all pixels.
Solution Approach 2:
The patent implements parameter changes by adjusting the driving range parameter of driving transistors based on the current-luminance ratio characteristics of different pixel types. The driving range is modified as a key parameter to compensate for the inherent differences in luminance efficiency among red, green, and blue pixels, thereby achieving consistent color accuracy across the display.
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 configuration minimizes color variation at low gray levels by making the luminance less sensitive to current variations, thereby enhancing color accuracy and display quality.
Implementation Method 1
Electrons injected from a cathode electrode and holes injected from an anode electrode are combined with each other in the organic light emitting layer to form excitons. Light is emitted while the excitons discharge energy.
Data Source
AI summary
An organic light emitting diode display includes: a plurality of pixels including a first pixel, a second pixel, and a third pixel connected to the plurality of scan lines and the plurality of data lines, wherein each pixel includes a switching transistor connected to a corresponding one of the scan lines and a corresponding one of the data lines, a driving transistor connected to the switching transistor, and an organic light emitting diode electrically connected to the driving transistor, and the driving range of the driving transistor of at least one pixel among the first pixel, the second pixel, and the third pixel is different from the driving range of the driving transistor of the remaining pixels.