Display Panel Data Current Circuit With Threshold Voltage Compensation
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Solution Overview
Problem
The existing pixel driving circuits generate data signal currents that deviate from the data signal voltage due to the threshold voltage of transistors, leading to poor uniformity in display panels as different circuits produce varying luminosity, resulting in non-uniform display.
Innovation Solution
A circuit that generates a data signal current includes a voltage module, a control module with a second capacitor to store the data signal voltage, a compensation control module to provide the transistor's threshold voltage, and a first capacitor to store the gate voltage of the current output transistor, ensuring the data signal current matches the data signal voltage by compensating for the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a transistor is used to generate the data signal current, then the data signal voltage can be converted into data signal current, but the threshold voltage of the transistor causes deviation between the converted current and the original voltage, resulting in poor display uniformity
Solution Approach 1:
The patent introduces a compensation transistor and compensation capacitor as intermediary elements. The compensation transistor's threshold voltage is used to offset the threshold voltage effect in the data signal transistor, while the compensation capacitor stores and transfers the compensation voltage. This intermediary mechanism enables precise compensation without requiring direct modification of the transistor characteristics, thereby improving current-voltage matching accuracy and display uniformity.
Solution Approach 2:
The patent dynamically adjusts the gate voltage of the data signal transistor by introducing a compensation voltage that changes based on the transistor's threshold voltage. Through the compensation control circuit, the gate voltage parameter is modified to counteract the threshold voltage effect, ensuring that the data signal current accurately reflects the data signal voltage despite variations in transistor parameters.
2Device complexity
If the threshold voltage of the current output transistor is not compensated, then the circuit structure remains simple, but the data signal current deviates from the data signal voltage, causing non-uniform luminosity across the display panel
Solution Approach 1:
The patent segments the circuit into distinct functional modules: a compensation control module that generates compensation signals, a compensation transistor dedicated to threshold voltage compensation, and a compensation capacitor for voltage storage. This segmentation allows the compensation function to be added without significantly complicating the overall circuit structure, as each module performs a specific function and can be independently optimized or replaced.
Solution Approach 2:
The compensation transistor is configured to automatically provide its own threshold voltage as the compensation voltage to the data signal transistor. This self-service mechanism eliminates the need for external compensation voltage generation circuits, reducing overall circuit complexity while still achieving threshold voltage compensation and improving luminosity uniformity.
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 improves the matching between data signal voltage and current, enhancing the uniformity of the display panel by eliminating the impact of the transistor's threshold voltage on the data signal current, resulting in consistent luminosity across the display.
Implementation Method 1
the control module includes at least one second capacitor, a second terminal of the second capacitor is connected to a first power supply terminal of the circuit, and the second capacitor is configured to store the data signal voltage
Implementation Method 2
a first terminal of the first capacitor is connected to the gate of the current output transistor, and a second terminal of the first capacitor is connected to the first power supply terminal, so that the first capacitor stores the voltage of the gate of the current output transistor
Data Source
AI summary
The present disclosure describes a display panel and a circuit to generate a data signal current included thereof. The circuit further comprises a signal voltage module to generate a primary signal voltage and send to a second storage capacitor in a control module to output a data signal voltage. The second storage capacitor is coupled to a first storage capacitor and a gate of a current output transistor, so that the primary signal voltage is stored at the joint node. A threshold voltage of the current output transistor, generated by a voltage compensation module, is then added on to the gate of the current output transistor, so that an output current compensated by the threshold voltage is realized.