OLED Display Transistor Zinc Oxide Active Layer Photo Sensor
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Solution Overview
Problem
The existing OLED displays face challenges in maintaining stable luminous efficiency and driving efficiency over time due to deterioration of thin film transistors, which affects the display quality and lifespan.
Innovation Solution
Incorporating a photo sensor with a second active layer made of amorphous silicon between the substrate and the organic emission layer, and using zinc oxide in the active layers of the thin film transistors to improve sensing and driving efficiency, along with a light blocking layer to enhance light emission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thin film transistors are used in OLED displays, then the device can be manufactured with standard processes, but the driving efficiency deteriorates over time affecting display quality and lifespan
Solution Approach 1:
The patent changes the material parameter of the thin film transistor active layer from conventional materials to zinc oxide (ZnO), which has superior electrical characteristics and stability. This material substitution improves the driving efficiency stability and extends the display lifespan by preventing performance deterioration over time.
Solution Approach 2:
The patent employs a composite structure combining zinc oxide active layer with amorphous silicon photo sensor layer. This composite material approach leverages the high electron mobility of ZnO for transistor performance and the light-sensing properties of amorphous silicon, achieving both improved driving efficiency and enhanced photo sensing capability.
2Reliability
If a photo sensor is added to sense light emitted from the organic emission layer, then the luminous efficiency can be improved, but the device complexity increases
Solution Approach 1:
The patent merges the photo sensor functionality directly into the display structure by forming the second active layer of amorphous silicon in the same device stack. This integration allows the photo sensor to sense light emitted from the organic emission layer without requiring separate external sensing components, thereby improving luminous efficiency control while minimizing additional complexity.
Solution Approach 2:
The amorphous silicon layer serves multiple functions: it acts as the photo sensor active layer for detecting emitted light, and simultaneously functions as part of the thin film transistor structure. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.
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 luminous efficiency of the organic light emitting element and the driving efficiency of the thin film transistors, leading to improved display quality and extended lifespan by compensating for transistor deterioration.
Implementation Method 1
a photo sensor disposed between the substrate and the organic emission layer, and including a second active layer that senses light emitted from the organic emission layer
Implementation Method 2
an organic light emitting element having a first electrode formed on the substrate, an organic emission layer disposed on the first electrode, and a second electrode disposed on the organic emission layer
Data Source
AI summary
An organic light emitting diode (OLED) display includes a substrate, an organic light emitting element including a first electrode, an organic emission layer, and a second electrode on the substrate, a driving thin film transistor turning on/off first power supplied to the first electrode and including a first active layer including zinc oxide (ZnO), a photo sensor disposed between the substrate and the organic emission layer and including a second active layer sensing light emitted from the organic emission layer, and a controller controlling at least one of the first power and a second power supplied to the second electrode according to the intensity of the light sensed by the photo sensor.