OLED Pixel Circuit Threshold Voltage Compensation
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Solution Overview
Problem
In OLED display devices, variations in threshold voltage of driving transistors across different pixel circuits or over time lead to inconsistent display luminance and poor display effects due to varying currents flowing through the OLED, even when driven by the same data voltage.
Innovation Solution
A pixel circuit design that includes a drive module, collection module, data write module, storage module, and light emission control module, where the threshold voltage is collected and stored independently of the drive module, allowing the light emission module to be driven based on stored voltage, thereby decoupling the driving current from the threshold voltage of the transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pixel circuit design is used, then device complexity is low, but display uniformity deteriorates due to threshold voltage variations
Solution Approach 1:
The pixel circuit is divided into multiple functional modules: drive module, collection module, data write module, storage module, and light emission control module. Each module performs a specific function, allowing independent optimization and reducing the impact of threshold voltage variations on display uniformity.
Solution Approach 2:
A storage module is introduced as an intermediary between the drive module and the light emission control module. This storage module stores the threshold voltage value and provides it to the light emission control module, enabling compensation for threshold voltage variations and improving display uniformity without directly increasing circuit complexity.
2Manufacturing precision
If threshold voltage compensation is implemented, then display uniformity improves, but device complexity increases
Solution Approach 1:
The collection module automatically collects the threshold voltage value from the drive module and stores it in the storage module without external intervention. This self-service mechanism enables the circuit to compensate for threshold voltage variations automatically, improving display uniformity while minimizing the increase in device complexity.
3Reliability
If multiple modules are added to compensate for threshold voltage, then display effect improves, but ease of manufacture deteriorates
Solution Approach 1:
The storage module serves multiple functions: it stores the threshold voltage value, provides compensation data to the light emission control module, and maintains circuit stability. This multi-functionality improves display reliability while minimizing the increase in manufacturing complexity compared to adding separate dedicated compensation circuits for each function.
Data Source
AI summary
A pixel circuit is provided. The pixel circuit includes a drive module, a collection module, a data write module, a storage module, a light emission control module, and a light emission module, wherein the data write module is configured to write a voltage at a data signal terminal into the storage module, wherein the collection module is configured to collect a threshold voltage of the drive module and write the threshold voltage into the storage module, wherein the storage module is configured to store a driving voltage for driving the drive module, wherein the drive module is configured to drive the light emission module to emit light according to the driving voltage stored by the storage module, and wherein the light emission control module is configured to control the drive module for driving the light emission module.