OLED Display Voltage Controller for Brightness Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
OLED display devices face issues with non-uniform brightness and incorrect color representation due to differences in transistor characteristics, leading to degraded image quality, especially when using the current driving method.
Innovation Solution
Incorporating a voltage controller that outputs a bias voltage to compensate for transistor characteristics, ensuring uniform brightness across different driving blocks by using a look-up table and variable resistance to adjust the bias voltage based on measured average brightness, and compensating threshold voltages of sink transistors to maintain consistent current supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a current driving method is used to drive OLED display devices, then the device can operate with simple control, but the brightness becomes non-uniform and color representation becomes incorrect due to sensitivity differences among R, G, and B colors
Solution Approach 1:
The patent changes the driving parameter from current-driven to voltage-driven mode. By applying voltage signals to the transistor gates rather than direct current, the system achieves uniform brightness across different color pixels while maintaining operational simplicity through automated voltage control mechanisms.
Solution Approach 2:
The patent incorporates feedback mechanisms through voltage control circuits that automatically adjust voltage levels based on the actual performance of each pixel. This feedback system compensates for sensitivity differences among R, G, and B pixels, ensuring uniform brightness without requiring complex manual adjustment.
2Manufacturing precision
If voltage driving method is adopted to drive OLED display devices, then brightness uniformity improves, but the device complexity increases due to additional control circuits
Solution Approach 1:
The patent designs voltage control circuits that serve multiple functions: they provide voltage driving for brightness uniformity, compensate for transistor characteristic variations, and enable color accuracy adjustment. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The patent merges voltage control and compensation functions into integrated circuits that work together seamlessly. By combining multiple control functions into unified circuit blocks, the patent achieves brightness uniformity and color accuracy while minimizing the total number of discrete components and control pathways required.
3Ease of manufacture
If transistor characteristics vary across different driving blocks, then manufacturing tolerance is easier to achieve, but image quality degrades due to non-uniform brightness and color
Solution Approach 1:
The patent applies local quality adjustment by providing individual voltage control for each driving block or pixel. Instead of using a single uniform control signal, the system adjusts voltage levels locally to compensate for transistor characteristic variations specific to each block, thereby maintaining image quality uniformity while accepting manufacturing tolerances.
Solution Approach 2:
The patent implements preliminary action through pre-characterization and pre-compensation of transistor properties. By measuring and storing transistor characteristics during manufacturing, the system can pre-calculate and apply appropriate voltage compensation values before the display operates, ensuring uniform image quality without requiring complex real-time adjustment mechanisms.
Data Source
AI summary
An organic light emitting diode display device comprising a display panel, a plurality of light emitting diodes arranged on the display panel and having an optical amount varied according to a current amount, a sample/hold unit for supplying a current to the light emitting diodes, a D/A converter for controlling a current amount supplied to the light emitting diodes from the sample/hold unit by controlling a current amount supplied from the sample/hold unit according to image information, and a voltage controller for conducting or shielding a current between the D/A converter and the sample/hold unit by outputting a second bias voltage of which loss voltage has been compensated according to a characteristic of a transistor provided at the D/A converter to the D/A converter by receiving a first bias voltage.