Display Pixel Circuit Layout for Parasitic Capacitance Compensation
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Solution Overview
Problem
Luminance deviation occurs in display apparatus due to parasitic capacitance between wires or conductive traces.
Innovation Solution
Incorporation of a compensation transistor connected between the driving transistor's second terminal and gate electrode, a storage capacitor, and a boost capacitor, along with specific transistor configurations to compensate for threshold voltage and reduce luminance deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires or conductive traces are used to control electrical signals, then the display apparatus can function, but parasitic capacitance occurs causing luminance deviation
Solution Approach 1:
The patent extracts and removes the harmful parasitic capacitance effect by introducing a compensation transistor that specifically counteracts the capacitive coupling between conductive traces. The compensation transistor creates an equal and opposite electrical effect to neutralize the parasitic capacitance, allowing the wires and conductive traces to function while eliminating the harmful luminance deviation.
Solution Approach 2:
The compensation transistor operates as a feedback mechanism that continuously monitors and adjusts the threshold voltage of the driving transistor based on the parasitic capacitance effects. By using the output signal from the driving transistor to control the compensation transistor, the system creates a closed-loop feedback that dynamically compensates for luminance deviations caused by parasitic capacitance.
2Reliability
If a compensation transistor is added to compensate for threshold voltage, then luminance deviation is reduced, but device complexity increases
Solution Approach 1:
The patent merges the compensation transistor with the existing driving transistor circuit configuration, integrating the compensation function into the same pixel circuit structure. The compensation transistor shares common components such as the gate electrode and conductive traces with the driving transistor, thereby reducing the overall increase in device complexity while still achieving effective threshold voltage compensation.
Solution Approach 2:
The compensation transistor is designed to serve multiple functions: it compensates for threshold voltage deviations, stabilizes the driving current, and maintains luminance uniformity across different pixels. By making the compensation transistor multi-functional, the patent reduces the need for separate dedicated compensation components, thereby limiting the increase in device complexity.
Data Source
AI summary
A display apparatus includes a light-emitting diode, a driving transistor configured to control a driving current supplied to the light-emitting diode, a compensation transistor connected between a second terminal of the driving transistor and a gate electrode of the driving transistor and configured to compensate for a threshold voltage of the driving transistor, a first connection electrode configured to connect the gate electrode of the driving transistor and a first terminal of the compensation transistor to each other, and a driving voltage line on an insulating layer covering the first connection electrode, covering the gate electrode of the driving transistor, and having an opening overlapping the first connection electrode.