Display Pixel Driving Circuit with Segmented Electrodes for Voltage Stability
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Solution Overview
Problem
The quality of images in display apparatuses is degraded due to voltage distortion in storage capacitors caused by signal lines, which affects process efficiency and image quality.
Innovation Solution
A display apparatus design that includes a separation insulating layer separating thin film transistors and storage capacitors, with different semiconductor materials used for the transistors and capacitors, and a stacked structure for capacitor electrodes to minimize voltage distortion and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If capacitor electrodes are simultaneously formed with conductive layers of thin film transistors to improve process efficiency, then manufacturing process efficiency is improved, but voltage stored in storage capacitor becomes distorted by signal lines
Solution Approach 1:
The capacitor electrode is divided into two separate layers: a first electrode layer formed simultaneously with the thin film transistor conductive layer, and a second electrode layer formed separately and disposed between the first electrode layer and the signal line. This segmentation allows the harmful interaction with the signal line to be isolated to only the second electrode layer, while the first electrode layer maintains its beneficial simultaneous formation with the transistor layer, thus resolving the contradiction between process efficiency and voltage stability.
Solution Approach 2:
The second electrode layer acts as an intermediary barrier between the signal line and the first electrode layer. By positioning this intermediate layer between the signal line and the first electrode layer, it shields the first electrode layer from the harmful electromagnetic interference of the signal line, thereby preventing voltage distortion while maintaining the process efficiency benefit of simultaneous formation.
2Device complexity
If storage capacitor is formed in limited area by number of thin film transistors and their arrangements, then device complexity is reduced, but voltage stored in storage capacitor becomes distorted by signal lines
Solution Approach 1:
The solution moves the protective function from the planar dimension to the vertical dimension by stacking the second electrode layer above the first electrode layer and positioning it between the first electrode layer and the signal line. This vertical arrangement allows the capacitor to maintain its compact area while introducing a new spatial dimension that provides shielding against signal line interference, thus resolving the contradiction between device complexity and voltage stability.
Data Source
AI summary
A display apparatus includes a light-emitting device and a driving circuit disposed in each pixel area. The driving circuit electrically connected to the light-emitting device may include a first thin film transistor, a second thin film transistor and a storage capacitor. A second semiconductor pattern of the second thin film transistor may be made of a material different from a first semiconductor pattern of the first thin film transistor. A separation insulating layer may be disposed between the first semiconductor pattern and the second semiconductor pattern. The storage capacitor may include a first capacitor electrode and a second capacitor electrode, which are sequentially stacked on the separation insulating layer. The first capacitor electrode may have a stacked structure of a first electrode layer including the same material as the second semiconductor pattern and a second electrode layer including a material having lower resistance than the first electrode layer.