Pixel Structure Common Electrode Shielding Parasitic Capacitance
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Solution Overview
Problem
The proximity of the pixel electrode to the data line in liquid crystal displays increases parasitic capacitance, leading to charge interference and cross-talk effects, which complicates the fabrication process and increases costs due to the need for additional insulating layers and metal layers for shielding.
Innovation Solution
A method is developed to fabricate a pixel structure by forming a first patterned metal layer with a gate electrode, data lines, and a common electrode, followed by a semiconductor channel layer, passivation layer, and a conducting layer, where the common electrode is positioned above the data line segment, reducing parasitic capacitance without the need for additional metal layers or complex fabrication steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pixel electrode is positioned close to the data line, then the aperture ratio is improved, but parasitic capacitance increases causing charge interference and cross-talk effects
Solution Approach 1:
A common electrode layer is introduced as an intermediary between the pixel electrode and the data line. This intermediate layer acts as a shield that reduces the parasitic capacitance coupling between the pixel electrode and data line, allowing the pixel electrode to be positioned closer to the data line without suffering from charge interference and cross-talk effects, thereby improving aperture ratio while controlling parasitic capacitance
Solution Approach 2:
The solution transitions from a two-dimensional planar arrangement to a three-dimensional layered structure by adding the common electrode layer in the vertical dimension. This dimensional change allows the pixel electrode and data line to be positioned closer in the planar view (improving aperture ratio) while the common electrode layer provides shielding in the vertical dimension (reducing parasitic capacitance)
2Object-affected harmful factors
If a common electrode layer is added to shield parasitic capacitance, then charge interference is reduced, but fabrication complexity and costs increase due to additional layers and steps
Solution Approach 1:
The common electrode layer is merged with the existing data line structure in the fabrication process. By forming the common electrode layer as part of the metal layer that also creates the data line, the patent reduces fabrication complexity and costs while still achieving the shielding effect against parasitic capacitance and charge interference
3Object-affected harmful factors
If a common electrode layer is added to shield parasitic capacitance, then cross-talk effects are reduced, but fabrication time and costs increase
Solution Approach 1:
The common electrode layer is formed preliminarily during the metal layer fabrication process, before subsequent patterning and electrode formation steps. This preliminary action integrates the shielding function into the existing fabrication sequence, reducing additional fabrication time and costs while effectively reducing cross-talk effects between pixel electrodes and data lines
Data Source
AI summary
A pixel structure includes a first patterned metal layer, a gate insulating layer, a semiconductor channel layer, a second patterned metal layer, a passivation layer, and a conducting layer. A gate line of the second patterned metal layer is electrically connected by the conducting layer to a gate extension electrode of the first patterned metal layer. A source electrode of the second patterned metal layer is electrically connected by the conducting layer to a second data line segment of the first patterned metal layer. A method for fabricating a pixel structure is also disclosed herein.