OLED Touch Sensor Integration on Thin-Film Encapsulation
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Solution Overview
Problem
Current OLED display devices lack an efficient and integrated solution for simultaneous information display and input, particularly in terms of touch sensitivity and image quality uniformity, due to the complexity of their structural configurations.
Innovation Solution
The OLED display device incorporates a substrate with organic light emitting diodes, a thin film encapsulation layer, and a sensing TFT with an oxide semiconductor layer, which acts as a touch sensor to detect light variations and enable touch input while maintaining a simple structure and high image quality through a 2Tr-1Cap pixel structure and thin film encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a sensor is added to the OLED display device for touch input functionality, then the information input capability is improved, but the device complexity increases
Solution Approach 1:
The sensor is integrated directly onto the OLED display device structure, merging the display and touch input functions into a single unified device. The sensor is positioned on the thin film encapsulation layer, combining multiple functionalities (display and sensing) in one integrated structure rather than separate components
Solution Approach 2:
The OLED display device structure serves multiple functions: the thin film encapsulation layer not only protects the OLED but also serves as a substrate for the sensor. The same structural layers (substrate, encapsulation) support both light emission and touch sensing operations, making the device multi-functional
2Device complexity
If the sensor structure is simplified, then the device complexity is reduced, but the touch sensitivity may deteriorate
Solution Approach 1:
The sensor structure uses an oxide semiconductor layer specifically in the sensing region, which provides high mobility and sensitivity for touch detection. This localized use of high-performance material in the critical sensing area maintains touch sensitivity while keeping the overall structure simple and compatible with standard OLED manufacturing
3Adaptability or versatility
If more components are added for simultaneous display and input, then the functionality is improved, but the thickness increases
Solution Approach 1:
The sensor structure is nested within the existing OLED display layers. The sensor is formed on the thin film encapsulation layer, utilizing the existing structural framework. This nested arrangement allows the sensor to be integrated within the display device's thickness rather than adding a separate external layer, maintaining a relatively thin profile while enabling dual functionality
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 allows for improved performance in both information display and input functionality with enhanced touch sensitivity and image uniformity, maintaining a relatively simple structure and small thickness.
Implementation Method 1
the oxide semiconductor layer overlapping the sensing gate electrode... acts as a touch sensor to detect light variations
Data Source
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AI summary
An organic light emitting diode display device includes a substrate, a plurality of organic light emitting diodes on the substrate, a thin film encapsulation layer on the organic light emitting diodes, and at least one sensor on the thin film encapsulation layer, the sensor including a sensing gate electrode, an oxide semiconductor layer overlapping the sensing gate electrode, a sensing source electrode connected to the oxide semiconductor layer, and a sensing drain electrode spaced apart from the sensing source electrode and connected to the oxide semiconductor layer.