Display Pixel Dummy Transistor Leakage Current Compensation
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Solution Overview
Problem
Display devices experience degradation in quality due to leakage currents generated by parasitic capacitors, which affect the driving of light emitting elements.
Innovation Solution
The display device incorporates a pixel structure with specific transistors and a dummy capacitor to manage voltage levels and reduce leakage currents, including a first transistor connected to a power line and a light emitting element, a second transistor connected to a data line, and a dummy transistor receiving a reference voltage set to the average of data voltages, with control signals and scan signals optimized to minimize leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel structure with transistors is used to drive light emitting elements, then the display device can operate and display images, but leakage current is generated due to parasitic capacitors which degrades display quality
Solution Approach 1:
A dummy transistor is introduced as an intermediary component between the third transistor and the second node. This dummy transistor includes a parasitic capacitor that acts as a mediator to compensate for the parasitic capacitor of the third transistor, thereby canceling out the harmful leakage current effects and improving display quality
Solution Approach 2:
The invention converts the harmful parasitic capacitor of the dummy transistor into a beneficial component. By deliberately designing the dummy transistor with a parasitic capacitor that matches the third transistor's parasitic capacitor, the harmful leakage current is transformed into a compensatory mechanism that improves overall pixel performance and reduces display quality degradation
2Ease of operation
If the magnitude of control signals is increased to improve switching performance, then transistor switching becomes more effective, but the leakage current increases due to larger voltage differences across parasitic capacitors
Solution Approach 1:
The dummy transistor is configured to create equipotential conditions that balance the voltage differences across parasitic capacitors. By matching the parasitic capacitor values and configuring the circuit symmetrically, the invention reduces potential differences that would otherwise drive leakage current, allowing effective switching with reduced harmful effects
Data Source
AI summary
A display device includes a pixel, wherein the pixel includes a light emitting element, a first transistor connected to a first power line and the light emitting element and controlled by a voltage of a first node, a second transistor connected to a data line and the first transistor and controlled by an i-th scan signal, a third-first transistor connected to the first transistor and a second node and controlled by a first control signal, a third transistor connected to the second node and the first node and controlled by a second control signal, and a dummy transistor including a first electrode receiving a reference voltage, a second electrode connected to the second node, and a control electrode connected to an emission line.