OLED Display Voltage Drop Compensation via Alternating Data Lines
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Solution Overview
Problem
Conventional organic light emitting diode (OLED) display devices with two driving thin film transistors per pixel face challenges in maintaining a desired gray level due to voltage drop caused by resistance in the power supply line, leading to stress on the driving thin film transistors and suboptimal performance.
Innovation Solution
The implementation of a data driving circuit and gate driver system that alternately supplies real and inverse data voltages to the first and second data lines, along with a reset pulse supply unit to reset the driving thin film transistors, compensates for the voltage drop by selectively turning on the driving transistors and supplying the high potential power voltage to the OLED, ensuring accurate gray level representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power supply line is used to supply high potential power voltage to all pixels, then the device complexity is reduced, but voltage drop occurs due to resistance in the power supply line causing inaccurate gray level representation
Solution Approach 1:
The power supply system is segmented into multiple independent power supply lines, each serving specific pixels. This segmentation allows each line to supply power with minimal voltage drop, ensuring accurate gray level representation while maintaining manageable device complexity through organized distribution.
Solution Approach 2:
Different power supply lines are assigned to different regions or groups of pixels based on their specific voltage requirements and positions. This local quality approach ensures that each pixel group receives optimized power supply with appropriate voltage levels, compensating for resistance effects in each local region.
2Reliability
If two driving thin film transistors are used per pixel to reduce stress on individual transistors, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Two driving thin film transistors in each pixel are merged to share the driving load for the OLED. This combining approach distributes the stress and operating conditions across both transistors, improving reliability by preventing single-transistor failure modes while maintaining a unified pixel output.
Solution Approach 2:
The two driving thin film transistors operate in an alternating periodic manner, with each transistor being selectively turned on during different time periods. This periodic action allows one transistor to rest while the other is active, reducing cumulative stress and heat generation on individual transistors, thereby improving reliability.
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 solution effectively compensates for the voltage drop across the power supply line, allowing for precise control of the driving voltage to each pixel, thereby enabling the representation of desired gray levels and reducing stress on the driving transistors, thus enhancing the overall performance of the OLED display device.
Implementation Method 1
an organic light emitting diode which emits light by a re-combination of an electron and a hole
Data Source
AI summary
An organic light emitting diode display device and a driving method thereof are disclosed. The organic light emitting diode display device comprises: a display panel having an m-number of first data lines and an n-number of gate lines crossing each other, an m-number of second data lines and the n-number of gate lines crossing each other, pixels formed at common crossing regions, and an n-number of reset lines arranged corresponding to the n-number of gate lines one by one and connected to the adjacent pixels; a data driving circuit for converting input digital data into a real data voltage and an inverse data voltage and selectively supplying the real data voltage and the inverted data voltage to the first and second data lines; a gate driver for sequentially supplying scan pulses to the gate lines; and a reset pulse supply unit for sequentially supplying reset pulses to the reset lines.