OLED Pixel Dual Storage Capacitor Structure for High Resolution
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Solution Overview
Problem
In high-resolution OLED displays, the storage capacitance is reduced due to the decreasing size of pixels, which affects the performance and efficiency of the display.
Innovation Solution
The design incorporates a dual storage capacitor structure within each pixel, with the first storage capacitor including a driving gate electrode as its lower storage electrode and a portion of the driving voltage line as its upper storage electrode, and a second storage capacitor separated from the first, both overlapping the driving voltage line, to maximize storage capacitance. This configuration includes a storage connecting member to connect the storage electrodes and an initialization voltage line to initialize the driving transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If display resolution is increased, then image quality is improved, but storage capacitance decreases
Solution Approach 1:
The storage capacitor is divided into two separate capacitors (first storage capacitor and second storage capacitor) within each pixel. This segmentation allows the total storage capacitance to be distributed across multiple components, enabling sufficient total capacitance even when pixel area is reduced for high resolution displays.
Solution Approach 2:
The patent utilizes the third dimension (vertical stacking) by forming capacitors at different heights within the pixel structure. The first storage capacitor uses the gate insulating layer as dielectric, while the second storage capacitor uses an additional insulating layer, effectively using vertical space to increase total storage capacitance without increasing pixel area.
2Length of moving object
If pixel size is decreased, then display resolution is improved, but storage capacitance decreases
Solution Approach 1:
The patent embeds multiple functional elements within the pixel structure, including nesting the first and second storage capacitors within the same pixel area. The capacitors are formed using different layers and positions, effectively nesting storage functions within the constrained pixel volume to maintain sufficient capacitance despite smaller pixel dimensions.
Solution Approach 2:
By utilizing vertical stacking with multiple insulating layers at different heights, the patent increases storage capacitance in the vertical dimension rather than expanding horizontally. This allows smaller pixel size while maintaining adequate storage capacitance through three-dimensional space utilization.
3Device complexity
If a single storage capacitor is used, then device complexity is reduced, but storage capacitance is insufficient
Solution Approach 1:
The storage function is segmented into two separate capacitors with distinct structures and dielectric layers. The first storage capacitor uses the gate insulating layer, while the second storage capacitor uses an additional insulating layer, allowing each capacitor to contribute to total capacitance and achieving sufficient storage capacity.
Solution Approach 2:
The gate insulating layer serves dual purposes: as the dielectric for the first storage capacitor and as part of the transistor gate structure. This multi-functionality allows the system to achieve sufficient storage capacitance through the first capacitor while the second capacitor provides additional capacitance, reducing the need for overly complex dedicated storage structures.
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 approach effectively maximizes storage capacitance, enhancing the display's performance and resolution by maintaining sufficient charge storage despite the smaller pixel size, thereby improving the overall display quality and contrast ratio.
Implementation Method 1
Electrons injected from a cathode electrode and holes injected from an anode electrode are bonded to each other in the organic light emitting layer to form excitons. Light is emitted when the excitons discharge energy.
Implementation Method 2
The capacitor includes a storage capacitor overlapping the driving transistor, and since the size of the pixel decreases with increased display resolution, storage capacitance of the storage capacitor also decreases.
Data Source
AI summary
An organic light-emitting diode (OLED) display is disclosed. In one aspect, the display includes a substrate, a scan line formed over the substrate and configured to provide a scan signal, and a data line crossing the scan line and configured to provide a data voltage. The display also includes a driving voltage line crossing the scan line and configured to provide a driving voltage, a switching transistor electrically connected to the scan line and the data line, and a driving transistor electrically connected to the switching transistor and including a driving gate electrode and a driving channel overlapping each other in the depth dimension of the display. A first storage capacitor overlaps the driving channel in the depth dimension and includes a portion of the driving voltage line. A second storage capacitor is separated from the first storage capacitor and overlaps the portion of the driving voltage line.