Pixel Circuit Compensation Without Extra Reference Wiring
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Solution Overview
Problem
Existing organic light-emitting display devices face challenges in maintaining uniform electrical characteristics across pixels due to manufacturing process deviations, leading to reduced pixel aperture ratio and PPI (pixels per inch) due to the need for additional voltage sources and wires in internal compensation circuits.
Innovation Solution
A pixel circuit design that compensates for variations in electrical characteristics of driving elements in real time without requiring additional wiring for reference voltages, utilizing a switch-based architecture with synchronized gate signals to manage pixel operations in initialization, sensing, data writing, and light emission periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal compensation circuit is added to compensate for electrical characteristic deviations, then pixel electrical characteristic uniformity is improved, but pixel aperture ratio and PPI deteriorate due to additional voltage sources and wires
Solution Approach 1:
The patent merges the light emitting element's cathode electrode with the pixel circuit's second node, eliminating the need for a separate reference voltage line. The cathode electrode serves dual purposes: as part of the light emitting structure and as a reference potential node for the compensation circuit, thereby reducing wiring complexity while maintaining compensation functionality
Solution Approach 2:
The second node serves multiple functions: it acts as the cathode connection for the light emitting element, provides the reference voltage node for the capacitor in the compensation circuit, and serves as a common potential reference for the driving element. This multi-functionality eliminates the need for dedicated reference voltage wiring
2Reliability
If internal compensation circuit is added to compensate for electrical characteristic deviations, then pixel electrical characteristic uniformity is improved, but device complexity increases due to additional voltage sources and wires
Solution Approach 1:
The patent merges the light emitting element's cathode electrode with the pixel circuit's second node, eliminating the need for a separate reference voltage line. The cathode electrode serves dual purposes: as part of the light emitting structure and as a reference potential node for the compensation circuit, thereby reducing wiring complexity while maintaining compensation functionality
Solution Approach 2:
The second node serves multiple functions: it acts as the cathode connection for the light emitting element, provides the reference voltage node for the capacitor in the compensation circuit, and serves as a common potential reference for the driving element. This multi-functionality eliminates the need for dedicated reference voltage wiring
Data Source
AI summary
The present disclosure relates to a pixel circuit and a display device including the same. The pixel circuit includes: a first voltage node; a second voltage node; a driving element including a first electrode to which a pixel driving voltage is applied, a gate electrode connected to a first node, and a second electrode connected to a second node; a light emitting element including an anode electrode and a cathode electrode and configured to be driven by a current from the driving element, a capacitor connected between the first node and the second node; a first switch element connected between a data line to which a data voltage is applied and the first node and turned on in response to a first gate signal; and a second switch element connected between the second node and the second voltage node and turned on in response to a second gate signal.