Light-emitting Device Electrode Overlap Strategy for Stray Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active-matrix light-emitting devices experience stray capacitances due to capacitive coupling between elements, leading to inaccurate control of light-emitting elements and reduced numerical aperture, which affects the efficiency and speed of operations.
Innovation Solution
Incorporating a capacitor electrically connected to the gate electrode of the driving transistor and strategically positioning the first electrode to overlap the capacitor, while ensuring it does not overlap switching elements, to reduce stray capacitance and allocate sufficient area for the first electrode, thereby preventing delay in switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the first electrode is formed to overlap switching elements to allocate sufficient area, then the area for the first electrode is increased, but stray capacitance between the first electrode and switching elements increases causing delay in switching operations
Solution Approach 1:
The patent extracts the harmful capacitive coupling by introducing a capacitor structure that is electrically connected to the gate electrode of the driving transistor. The first electrode is positioned to overlap this capacitor rather than switching elements, thereby separating the useful overlap (for area allocation) from the harmful overlap (stray capacitance with switching elements).
Solution Approach 2:
The capacitor serves as an intermediary element between the first electrode and the gate electrode. By positioning the first electrode to overlap the capacitor, the patent creates an intermediate structure that allows area allocation without direct capacitive coupling to switching elements, thus mediating between the conflicting requirements of area and switching speed.
2Illumination intensity
If layers of transistors and light-emitting elements are laminated to improve numerical aperture, then the numerical aperture is improved, but capacitive coupling occurs between elements in proximity causing inaccurate control
Solution Approach 1:
The patent applies local quality by differentiating the overlap relationships of the first electrode with different elements. The first electrode is designed to overlap the capacitor (useful for area) while avoiding overlap with switching elements (harmful for control accuracy). This localized differentiation of overlap quality resolves the contradiction between numerical aperture improvement and control accuracy.
Solution Approach 2:
The patent extracts the harmful capacitive coupling effect by deliberately positioning the first electrode to overlap only the capacitor and not the switching elements. This extraction of the harmful interaction allows the laminated structure to maintain both high numerical aperture and accurate control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces stray capacitance, allowing for high-speed operation of the selecting and initializing transistors, accurate control of light-emitting elements, and improved numerical aperture by minimizing capacitive coupling between elements.
Implementation Method 1
a capacitor (e.g., a capacitor C1 shown in FIG. 2 or a capacitor C2 shown in FIG. 21 or FIG. 32) electrically connected to a gate electrode of the driving transistor
Implementation Method 2
capacitive coupling occurs between elements that are located in proximity to each other. That is, stray capacitances could arise between such elements
Data Source
AI summary
A light-emitting device includes a power feeding line to which a predetermined voltage is supplied; a light-emitting element formed of a first electrode, a second electrode, and a light-emitting layer interposed between the first electrode and the second electrode; and a driving transistor that controls the amount of current supplied to the light-emitting element from the power feeding line. The power feeding line includes a portion interposed between the first electrode and the driving transistor.