Transparent Substrate Pixel Architecture for AMOLED Aperture Ratio
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Solution Overview
Problem
Active matrix organic light emitting device (AMOLED) displays have limited aperture ratios due to the necessity of drive transistors and other circuitry, which restricts the pixel's luminance and lifetime, especially in high-resolution displays where the distance between OLEDs and the size of these components are significant, leading to higher power consumption and reduced effectiveness.
Innovation Solution
A pixel structure is designed with a substantially transparent substrate, a drive transistor, and an organic light emitting device positioned on the opposite side, featuring a reflective layer with a concave shape to direct reflected light back onto the emitting device, thereby increasing the aperture ratio by minimizing the blocked emission surface area and reducing the need for space between OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drive transistors and other circuitry are included in the pixel structure, then the pixel can be operated and controlled, but the aperture ratio is reduced due to the area occupied by these components
Solution Approach 1:
The patent positions the drive transistor and other circuit components on the substrate in the same plane as the OLED, rather than stacking them vertically. This lateral arrangement allows light to pass through the OLED without being blocked by overhanging components, effectively increasing the aperture ratio while maintaining full operational control of the pixel.
Solution Approach 2:
The pixel structure is segmented into distinct functional zones: the OLED emission area, the drive transistor area, and the interconnect area. By spatially separating these functions and arranging them in parallel on the substrate, the design maximizes the emission area while providing sufficient space for all necessary circuit components to operate independently.
2Ease of manufacture
If the distance between adjacent OLEDs is increased to accommodate fabrication requirements, then manufacturing is easier, but the resolution of the display is reduced
Solution Approach 1:
By transitioning from a vertical stacking architecture to a lateral parallel arrangement, the patent eliminates the need for large vertical clearance between OLEDs. This allows adjacent OLEDs to be positioned much closer together horizontally, enabling high-resolution displays while maintaining standard fabrication capabilities.
3Use of energy by moving object
If the aperture ratio is increased to improve luminance, then power consumption is reduced, but the area for circuit components is reduced
Solution Approach 1:
The lateral arrangement of components maximizes the aperture ratio by eliminating vertical obstructions to light, improving luminance efficiency and reducing power consumption. Simultaneously, the extended horizontal space on the substrate provides adequate room for all circuit components, resolving the trade-off between aperture size and circuit area.
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 enhances the aperture ratio, reducing power consumption and extending the OLED lifetime by lowering current density and voltage requirements, while allowing for higher resolution displays without stringent fabrication design rules, thus enabling more efficient light emission and improved display performance.
Implementation Method 1
a reflective layer disposed between the light emitting device and the drive transistor and having a reflective surface facing the light emitting device
Implementation Method 2
At least a portion of the reflective layer is preferably concave in shape to direct reflected light from the light emitting device back onto the light-emitting device
Data Source
AI summary
A pixel structure comprises a substantially transparent substrate, a drive transistor formed on the substrate, an organic light emitting device formed on the opposite side of the drive transistor from the substrate, a reflective layer disposed between the light emitting device and the drive transistor and having a reflective surface facing the light emitting device. The reflective layer forms an opening offset from the drive transistor for passing light emitted by the light emitting device to the substrate. At least a portion of the reflective layer is preferably concave in shape to direct reflected light from the light emitting device back onto the light-emitting device.