Display Pixel Circuit Shielding for Transistor Compensation Errors
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Solution Overview
Problem
Display devices experience compensation errors in transistors, which degrade image quality.
Innovation Solution
A display device design that includes a shielding electrode covering the drain electrode of a first transistor, preventing electrical connection and compensating for transistor errors, and incorporates multiple transistors and capacitors to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transistor structure is used without additional shielding, then the device complexity is low, but compensation errors occur in the transistor causing degraded image quality
Solution Approach 1:
A shielding electrode is introduced as an intermediary element between the drain electrode and surrounding conductive structures. This shielding electrode acts as a mediator that blocks unwanted electrical coupling and interference, preventing compensation errors in the transistor without fundamentally changing the core transistor structure. The shielding electrode is electrically connected to the source electrode, creating a grounded shield that isolates the drain electrode from external interference.
2Manufacturing precision
If a shielding electrode is added to prevent compensation errors, then image quality improves, but the device complexity and manufacturing steps increase
Solution Approach 1:
The shielding electrode is merged with the existing metal layers and conductive structures of the pixel circuit. Instead of being a completely separate component requiring independent fabrication, the shielding electrode is integrated into the multi-layer metal structure, sharing fabrication steps with other conductive elements. The shielding electrode is formed in the same metal layer as the drain and source electrodes, allowing simultaneous deposition and patterning processes.
Solution Approach 2:
The shielding electrode serves multiple functions simultaneously: it shields the drain electrode from external electrical interference, provides a reference voltage connection through its connection to the source electrode, and acts as part of the overall pixel circuit ground structure. This multi-functionality reduces the need for separate dedicated shielding components, simplifying the overall device architecture.
Data Source
AI summary
A display device comprises an active layer on a substrate, a first metal layer above the active layer, a second metal layer above the first metal layer, a first transistor comprising a semiconductor region in the active layer, a drain electrode on a first side of the semiconductor region, a source electrode on a second side opposite the first side of the semiconductor region, and a gate electrode in the second metal layer, a first capacitor comprising a first capacitor electrode in the first metal layer and electrically connected to the gate electrode of the first transistor, a second capacitor comprising a second capacitor electrode in the first metal layer and electrically connected to a driving voltage line supplying a driving voltage, and a shielding electrode in the second metal layer and overlapping with the first capacitor electrode, the second capacitor electrode, and the drain electrode of the first transistor.