Display Device Driving Transistor Multi-Mode Sensing Circuit
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Solution Overview
Problem
The complexity of sub-pixel circuits in electroluminescent display devices increases manufacturing costs and sensing time, necessitating a reduction in circuit complexity.
Innovation Solution
A display device with a driving transistor operating in saturation and switch modes, coupled with a sensor that integrates current from the source node to sense driving transistor characteristics, reduces circuit complexity by eliminating the need for additional switching transistors during sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional switching transistors and capacitors are added to the sub-pixel circuit for sensing and compensation, then measurement precision and reliability improve, but device complexity and manufacturing cost increase
Solution Approach 1:
The driving transistor is designed to perform multiple functions: it serves as the primary driving element for the light-emitting element and simultaneously functions as a sensing element during sensing mode. By utilizing the inherent electrical characteristics of the driving transistor (such as threshold voltage and mobility) during sensing operations, the patent eliminates the need for separate sensing transistors and capacitors, thereby reducing circuit complexity while maintaining sensing precision
Solution Approach 2:
The driving transistor senses its own characteristics by operating in different modes (driving mode and sensing mode). During sensing mode, the transistor's electrical properties are measured directly without requiring external sensing components, allowing the circuit to self-diagnose and self-compensate for variations in transistor parameters
2Reliability
If additional switching transistors and capacitors are added to the sub-pixel circuit for sensing and compensation, then reliability improves, but manufacturing cost increases
Solution Approach 1:
The driving transistor performs dual roles as both the light-emitting element driver and the sensing element. This multi-functionality reduces the total number of transistors and capacitors required in the sub-pixel circuit, simplifying the manufacturing process and reducing production costs while maintaining compensation reliability through direct measurement of the driving transistor's electrical characteristics
3Measurement precision
If additional switching transistors and capacitors are added to the sub-pixel circuit for sensing and compensation, then measurement precision improves, but time needed for sensing and compensation increases
Solution Approach 1:
The patent extracts the sensing function from separate dedicated sensing components and integrates it directly into the driving transistor's operation. By removing the need for additional switching transistors and capacitors specifically for sensing, the circuit undergoes fewer switching operations and requires less time for charge/discharge cycles, thereby reducing sensing time while maintaining measurement precision through direct electrical characteristic measurement
Data Source
AI summary
A display device according to an embodiment of the present disclosure includes a light-emitting element configured to emit light, a driving transistor configured to provide a high-level voltage to the light-emitting element, and a switching transistor configured to transfer a voltage input through a data line to a gate node of the driving transistor. The driving transistor operates in a saturation mode in which a voltage of a source node is saturated in response to a first data voltage input to the gate node, and operates in a switch mode in which the driving transistor operates as a switch in response to a second data voltage higher than the first data voltage, so that a driving current generated in the driving transistor is able to be sensed through the source node.