OLED Driving Circuit with Variable Current Scaling
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Solution Overview
Problem
The existing organic light-emitting diode display devices face issues with prolonged data line charging time and picture quality deterioration due to non-uniform current scaling and increased bias stress on driving TFTs, especially at low and high gray scales.
Innovation Solution
The proposed solution involves an organic light-emitting diode display device with a specific driving method that includes a data line, gate lines, an emission line, and capacitors, where a pre-charge voltage is supplied, and an up-scaling current is applied to reduce charging time and alleviate bias stress by non-linearly scaling the current based on gray scale ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant current scaling ratio is applied to all gray scales, then the manufacturing process is simple, but the data line charging time is prolonged at low gray scales and picture quality deteriorates
Solution Approach 1:
The patent applies dynamics by making the current scaling ratio variable rather than constant. The scaling ratio is dynamically adjusted based on the gray scale level, with higher ratios for low gray scales and lower ratios for high gray scales. This dynamic adaptation resolves the contradiction by optimizing charging time for each gray scale condition while maintaining manufacturing simplicity through automated ratio selection.
Solution Approach 2:
The patent changes the parameter of current scaling ratio from a fixed value to a variable value that depends on gray scale level. By implementing different scaling ratios for different gray scale ranges (e.g., 2:1 for low gray scales, 1:1 for high gray scales), the system optimizes data line charging time without complicating the manufacturing process, as the parameter change is implemented through control logic rather than hardware complexity.
2Device complexity
If a constant current scaling ratio is applied to all gray scales, then the device structure remains simple, but bias stress on driving TFTs increases at high gray scales
Solution Approach 1:
The patent applies dynamics by making the current scaling ratio variable rather than constant. The scaling ratio is dynamically adjusted based on the gray scale level, with higher ratios for low gray scales and lower ratios for high gray scales. This dynamic adaptation resolves the contradiction by optimizing charging time for each gray scale condition while maintaining manufacturing simplicity through automated ratio selection.
Solution Approach 2:
The patent changes the parameter of current scaling ratio from a fixed value to a variable value that depends on gray scale level. By implementing different scaling ratios for different gray scale ranges (e.g., 2:1 for low gray scales, 1:1 for high gray scales), the system optimizes data line charging time without complicating the manufacturing process, as the parameter change is implemented through control logic rather than hardware complexity.
3Ease of operation
If linear current scaling is used, then the driving method is simple, but picture quality uniformity deteriorates due to non-uniform charging characteristics
Solution Approach 1:
The patent changes the parameter of current scaling ratio from a fixed value to a variable value that depends on gray scale level. By implementing different scaling ratios for different gray scale ranges (e.g., 2:1 for low gray scales, 1:1 for high gray scales), the system optimizes data line charging time without complicating the manufacturing process, as the parameter change is implemented through control logic rather than hardware complexity.
Solution Approach 2:
The patent applies preliminary action by pre-charging the data line to a predetermined voltage level before applying the scaled current. This preliminary charging action ensures that the data line reaches the appropriate voltage state in advance, allowing the subsequent current scaling to produce uniform picture quality across different gray scales while maintaining driving method simplicity through automated control.
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 effectively reduces data line charging time and improves picture quality uniformity by adjusting current levels according to gray scale, thereby reducing the burden on driving TFTs and enhancing overall display quality.
Implementation Method 1
a first capacitor connected between the second gate line and the first node, and a second capacitor connected between the first node and the second node
Data Source
AI summary
An organic light-emitting diode display device includes a data line, a first and second gate lines crossing the data line, an emission line crossing the data line, an organic light-emitting diode device having an anode electrode and a cathode electrode, a high-level potential driving voltage source for supplying a high-level potential driving voltage to the anode electrode, a first switch element for connecting a cathode electrode of the organic light-emitting diode device to a first node, a second switch element for connecting the data line to a second node, a third switch element for connecting the second node to a ground voltage source, a driving element for adjusting a current flowing between the cathode electrode of the organic light-emitting diode device and the first node in accordance with a voltage of the first node, a first capacitor connected between the second gate line and the first node, and a second capacitor connected between the first node and the second node.